3. What Are Microbes?
• A microorganism is an organism that is
microscopic (usually too small to be seen
by the naked human eye).
• From our perspective, They can seem
Good, Bad, or Neither
4. True or False?
If all microbes were eliminated, humans
could not survive on earth.
We have identified most microbes.
Most microbes are potentially harmful to
humans or animals.
When we are healthy, our bodies do not
contain any microbes
9. Microorganism Names Tell a
Story…
• Names can be descriptive or honor a
scientist
• Names are “Latinized”
• Staphylococcus aureus refers to a grape-like
cluster (Staphylo-) of round (coccus)
golden colored (aureus) cells
10. Proper Names
• The name is italicized or underlined
• Only the first name (genus) is capitalized
• Often the first name is abbreviated
• Escherichia coli or E. coli
12. Microscopy
• 1665 Robert Hooke uses a microscope to
see individual cells.
• The beginning of Cell Theory: All living things
are made of cells that came from pre-existing cells.
• 1673 Leeuwenhoek observes live
microorganisms.
13. Spontaneous Generation VS. Biogenesis
• Spontaneous Generation: living things
come from nonliving things.
• Biogenesis: All living things come from
preexisting living cells
14. Francisco Redi 1668
Conditions Results
Three jars
covered
with fine net
No maggots
Three open
jars
Maggots
appeared
From where did the
maggots come?
What was the purpose of
the sealed jars?
Spontaneous generation
or biogenesis?
Johnathan Needham
1745
Conditions Results
Nutrient
broth
heated,
then placed
in sealed
flask
Microbial
growth
From where did the
microbes come?
Spontaneous generation
or biogenesis?
15. Spallanzani 1765
Conditions Results
Nutrient
broth
placed in
flask,
heated,
then sealed
No
microbial
growth
Spontaneous generation
or biogenesis?
Louis Pasteur
1861
Conditions Results
Nutrient broth
placed in
flask, heated,
not sealed
Microbial
growth
Nutrient broth
placed in
flask, heated,
then sealed
No microbial
growth
Spontaneous generation or
biogenesis?
17. Fermentation/Pasteurization
• Louis Pasteur was contracted by French
merchants to figure out why beer and wine
soured.
• He showed that good microorganisms changed
sugar to alcohol in the absence of air
• He showed that bad microorganisms changed
the alcohol to vinegar in the presence of air
• He showed the connection between food
spoilage and microorganisms.
18. Germ Theory
• Accepted thought was that disease was
caused by misdeeds
• 1860’s Joseph Lister began treating
surgical wounds with a phenol solution
• 1876 Robert Koch developed steps to
show that a specific microbe causes
a specific disease aka Koch’s
postulates
19. Vaccination
An ounce of prevention
• 1796 Edward Jenner small pox and cow
pox
• 1880 Louis Pasteur showed why vaccines
work
20. Chemotherapy
A Pound of Cure
• Treatment of disease by using chemicals
• 1910 Ehrlich discovers salvarsan
• Alexander Fleming and penicillin
– Antibiotic resistance
21. Study of Microbiology
• Bacteriology: Study of Bacteria
• Mycology: Study of Fungi
• Parasitology: Study of
Protozoa and parasitic worms
• Immunology: Study of
immunity
• Virology: Study of viruses
22. Microbes and Human Welfare
• Sewage Treatment
• Bioremediation
• Pest Control
• Recombinant DNA Technology
23. Microbes and Human Disease
• Normal flora or microbiota help prevent growth
of pathogens
• Every individual’s response to a pathogen is
different
• Emerging infectious diseases: New diseases
and diseases increasing in incidence
24. Do These Sound Familiar?
• Bird Flu
• Sars
• West Nile
• Mad Cow
• E. coli O157:H7
• Ebola
• Flesh-eating bacteria
• Aids
• Swine Flu H1N1
