BIOL 260-General Microbiology
Instructor: Traci Kinkel, Ph.D
Welcome to BIOL 260: Microbiology!
• First day:
– Review of Syllabus
– Sign-in
– Introduce the course, review course
expectations
– 5-min quiz
– Begin with first lab
• Exercise 3: Microscope Lab
What is microbiology?
What is microbiology?
• The scientific discipline which studies
microbes or microorganisms
– Biology of microbes
– The interaction of microbes with other
microbes, the environment, and humans
What are examples of microbes?
What are examples of microbes?
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Algae
Fungi
Protozoa
Bacteria
Viruses
1. Algae
2. Fungi
3. Protozoa
4. Bacteria
5. Viruses
• Which microbes are eukaryotes?
• Which are prokaryotes?
• Which can perform
photosynthesis?
• Which are classified based on
locomotion?
• Which have cell walls?
• Which have some type of
nucleic acid?
Types of Microbes
Types of Microbes: Algae
Types of Microbes: Protozoa
Types of Microbes: Fungi
Types of Microbes: Bacteria
Viruses, Viroids, Prions
Microorganisms are associated with
• Disease
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Cause of many epidemics in history
Bubonic plague (1346-1350)
Small pox
HIV
Malaria
Bacteria are associated with
• Normal microbiota (normal flora)
– The bacteria that are present on our bodies
Bacteria are associated with
• the environment
– Rhizobium
• Food products
• Recombinant DNA products
History of Microbiology
• It all started with the microscope!
– Zacharis Janssen (1600)
– Antoni van Leewenhoek (1632-1723)
– Robert Hooke (1665)
Zacharis Janssen’s microscope
• Modeled after the
telescope
• Consisted of two
lenses
• Magnified images 310X
Leewenhoek’s microscope
Where do cells come from?
• Spontaneous generation
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Francesco Redi (1668)
John Needham (1745)
Lazzaro Spallanzani (1765)
Louis Pasteur (1861)
• Biogenesis
– Rudolf Virchow (1858)
Pasteur’s flasks
John Tyndall questions Pasteur’s
experiments
• Could not reproduce Pasteur’s results
• Found that there were heat resistant forms of
microbes
• Same year (1876) Ferdinand Cohn discovers heat
resistant forms of bacteria called endospores
• 1877 Robert Koch demonstrates that anthrax
caused by Bacillus anthracis
Major Milestones in Microbiology
Major Milestones in Microbiology
New cells need to be placed in categories
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Aristotle-plant or animal kingdom
Kingdom Protista (1866)
Electron microscope (1940’s)
Kingdom Procaryotae (1968)
Carl Woese proposed 3 Domains (1978)
Three Domain System
Prokaryotes (Bacteria)
• Bacteria Domain (Eubacteria)
– Gram negative
– Gram positive
– No cell walls
• Archaea Domain (Archaebacteria)
– Methanogens
– Halophiles
– Thermophiles
Binomial system of nomenclature
• Genus and species
– Escherichia coli, E. coli
• Both names are in italics or underlined
Relationship of size and
resolution
Types of microscopes
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Brightfield
Darkfield
Phase Contrast
Fluorescent
Electron
Microscopy-Brightfield
Oil has same refractive index as
glass
Microscopy
Stained specimen
Wet mount
Microscopy
Stained specimen
Wet mount
Microscopy
Electron microscopes - maximum magnification 100,000X
Microscopy
Electron microscopes - maximum magnification 100,000X
“Color-enhanced”
Staining: key to visualization
• Simple
• Differential
• Special
Microscopic Techniques: Dyes and
Staining
•Simple stains
•Differential stains
Gram stain - separates
bacteria into two categories
based on type of cell wall
Acid Fast Stain
Gram-positive
Gram-negative
Microscopic Techniques: Dyes and
Staining
•Simple stains
•Differential stains
Gram stain - separates
bacteria into two categories
based on type of cell wall
Acid Fast Stain
Differential Stain: Acid Fast
Microscopic Techniques: Dyes and
Staining
Fluorescent dyes and tags
Special stain: Capsule Stain
Special stain: Endospore Stain
Special stain: Flagella Stain
Morphology of
Prokaryotic Cells:
Cell Shapes
Morphology of Prokaryotic Cells:
Cell Shapes
Morphology of Prokaryotic Cells:
Cell Groupings
Morphology of Prokaryotic Cells:
Multicellular Associations
Biofilm containing mixed species