Microbe of the Week

1
Microbe of the Week

• A Eukaryotic, budding, spherical yeast cell
• Bakers and
• brewers yeast
• Ferments sugars
• producing CO2
• and ethanol

10-15 microns diameter
2
Microbe of the Week

• Escherichia coli
• Common intestinal bacterium
• Most strains non-pathogenic

3
Escherichia coli
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Escherichia coli

• Gram negative rod
• Divides in 20 minutes under optimal conditions
• Widely used in molecular biology

5
Escherichia coli

• Some strains produce exotoxins that cause
  intestinal damage
• Example E. coli 0157

6
Microbe of the WeekStaphylococcus aureus
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Staphylococcus aureus

• Golden-colored colonies

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Staphylococcus aureus

• Behold Staphylococcus aureus,
• A gold-colored Gram positive coccus
• Staph lives on our skin
• And sometimes it gets in
• Making toxins that sure disagree with us!

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Staphylococcus aureus

• Gram positive coccus
• Grape-like clusters
• Common on skin and nose grows in high salt

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Staphylococcus aureus

• Opportunistic pathogen makes toxins
• Skin abscesses
• Food poisoning
• Toxic shock syndrome

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Staphylococcus aureus
12
Staphylococcus aureus
13
Microbe of the Week

• Influenza virus causes epidemic influenza
• An enveloped segmented ssRNA virus
• There are human adapted strains but also, equine,
  swine, domestic bird (chicken) Flu strians
• In nature, Influenza is a wild bird virus
• Influenza mutates rapidly and sometimes jumps
  species

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The Structure of an Influenza virus
Envelope Spikes Helical nucleoprotein
Influenza has ssRNA in 8 segments (8 genes)
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Microbe of the Week
Influenza virus is cultivated in embryonating
chicken eggs
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Microbe of the Week
Influenza virus undergoes mutational changes each
year necessitating a new vaccine strain be
prepared Antigenic Drift Periodically a
completely new strain emerges from pigs or birds
which is pathogenic for humans. Antigenic
Shift