Transcript Lab session 1

Lab session 1
• Media preparation
• Media sterilization
• Use and care of the microscope
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Media – nutrients
Used to grow microbes
Glucose – energy
Peptones – breakdown products of protein
Good source of nitrogen, amino acids
Yeast extract - vitamins
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Liquid medium – nutrient broth
Large amount of culture
Solid medium – nutrient agar
Agar – solidifying agent
Extracted from red algae
Polysaccharide
• Granules of agar from a commercial
source
• Add that to nutrient broth
• Heat the mixture to dissolve granules
• Solution cools down to 40oC agar
becomes a solid
Agar – good solidifying agent
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Microbes cannot breakdown agar
Cannot metabolize
No nutritional value
Stays a solid even in incubators
Study colony morphology
Isolate a specific species from a sample
• Agar – sterilized in the autoclave
• Temperature 121oC, pressure 15psi, 15
minutes
• Heat labile solutions – solutions of
enzymes
• Filtration
• Microbes stay on the surface of filter
• Solution free of microbes goes through the
filter
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Dry sterilization
Glassware – pipets
Oven – 180oC for 2 hours
Chemical sterilization
Disinfectant –clean table tops
Microscope
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Use of oil immersion objective
Focusing an object
Total magnification
Cleaning and storing