• Syllabus
• Expectations
– 12 quizzes – drop 1 – no make up quizzes/exercises
– Due date – turn in at beginning of lab
– Student preparation for lab
– Lab reports and questions – study tool
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• Read pp. 1 – 6
• Treat all microorganisms (bacteria, viruses, fungi) and chemicals as if they are hazardous
• Learn and practice the safest level of standard at all times
– No food, drinks in the lab
EVER
– Wash hands thoroughly, after handling microbes, before leaving lab, after removing gloves
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– Take nothing out of the lab
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– Open toed shoes
– Tie back long hair
– Gloves while handling microbes/staining
– Antiseptic if exposed
– Turn off Bunsen burner when not in use
– Eyewash
– Fire extinguisher
– Keep work area clear
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• Spills and broken glass
– Notify instructor immediately before attempting to clean up
• Disposal of Materials
– Broken glass – special container
– Biohazard Bag – for contaminated paper towels, gloves, etc.
– Test tubes – remove labels & place in racks
– Plates – place in disposal bucket
– Live cultures on slides – decontaminate/clean
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– Stained slides – clean and return to slide box
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• Keep work area free of clutter – do not keep books/papers on work area
• Wipe with 70% ethanol before and after lab
• All tubes must be in racks – do not lay tubes on table
• Always put paper towel on work area and soak it with 70% ethanol
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• Lecture text pp. 178- 182
• What is growth media
• Why do microbiologists need growth media?
• What are the requirements for a growth media?
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Physical States
•
Liquid
•
Semisolid
• Solid (can be liquefied)
• Solid (cannot be liquefied)
Chemical composition
•
Defined (synthetic, chemically defined)
•
Complex ( non-synthetic, not chemically defined)
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Liquid – broth ; does not solidify
Semisolid – contains solidifying agent
Solid – firm surface for colony formation
– Contains solidifying agent
– Liquefiable and nonliquefiable
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Figure 6.11 Slant tube containing solid media
Slant
Butt

• Synthetic – contains pure organic and inorganic compounds in an exact chemical formula
•
Complex or nonsynthetic
– contains at least one ingredient that is not chemically definable
•
General purpose media
– grows a broad range of microbes, usually nonsynthetic
• Enriched media – contains complex organic substances such as blood, serum, hemoglobin, or special growth factors required by fastidious microbes
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•
Culture Media
– Majority of prokaryotes have not been grown in culture medium
– Six types of general culture media
• Defined media
• Complex media
• Selective media
• Differential media
• Anaerobic media
• Transport media
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Figure 6.12 An example of the use of a selective medium
Bacterial colonies Fungal colonies pH 7.3
pH 5.6

Figure 6.13 The use of blood agar as a differential medium
Beta-hemolysis
Alpha-hemolysis
No hemolysis
(gamme-hemolysis)

Figure 6.14 The use of carbohydrate utilization tubes as differential media
Durham tube
(inverted tube to trap gas)
No fermentation Acid fermentation with gas

Figure 6.15 Use of MacConkey agar as a selective and differential medium-overview

Clamp
Chamber
Figure 6.16 An anaerobic culture system
Airtight lid
Palladium pellets to catalyze reaction removing O
2
Envelope containing chemicals to release CO
2 and H
2
Petri plates
Methylene blue
(anaerobic indicator)

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–
Nutrient broth
– liquid medium containing beef extract and peptone
–
Nutrient agar
– solid media containing beef extract, peptone, and agar
– Typticase Soy Broth or Agar – beef extract and soy extract
–
Brain Heart Infusion Broth and A gar – extract of beef heart and brain
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Most commonly used solidifying agent is agar
• A complex polysaccharide isolated from red algae
– Solid at room temperature, liquefies at boiling
(100 o C), does not re-solidify until it cools to
42 o C
– Provides framework to hold moisture and nutrients
– Not digestible for most microbes
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• Important points
– Careful measuring of materials
– Careful distribution
– Sterilization and verification
– Storage
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• Ubiquity?
• Work in groups of 2 -3
• Growth media – Nutrient Agar
• Label bottom of plates with #, initials & date
• Invert – why? Tape plates together
• Incubation T – 25 o
o
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