Transcript Introductory Microbiology

Bryan Paul
University of Alberta, Canada
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Introductory
Microbiology
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1. Know the history of emergence in microbiology
2. Know the people who contributes to the emergence of the
subject.
3. Know why microbiology is important and appreciate the
beauty of it.
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Objectives
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History
• A Dutch amateur microscope builder
• First observation of ‘animalcules’
• Source of observation are from biofilm of an old man teeth
and ditch at the back of his house.
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Antonie van Leeuwenhoek (1632-1723)
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Figure showing his microscope and his observation
Images: history.org and Kunal Bheecarry
Spontaneous generation
Theory
• Lucretius
 He said that disease is cause by invisible living creatures
• Aristotles
 Comes out with the spontaneous generation theory
 The theory is used to logically deduce the emergence of
organisms from specific sources.
 The theory lasted for 2000 years until it was relinquish by
modern biologist.
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1. 384-55BC
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2.
1626 – 1799
• John Needham
 Observed broth that had been boiled and seal in a jar still became
turbid.
 Agree with spontaneous generation theory.
• Lazzaro Spallanzani
 Observed that sealed flask of broth that were then boiled did not
become turbid
 Infer that it may be air that cause growth of microbes
 Disapprove spontaneous generation theory.
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• Francesco Redi
 Notice that cheesecloth over meat did not induce the emergence of
maggots
 Disapprove spontaneous generation theory
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• First scientist to connect the relationship
between cause (microorganism, bacteria,
etc) and effect (disease, growth, etc).
• Other than that, he is also the first scientist
that;
discover fermentation process
determining the nature of disease
Pasteurisation process
And ultimately disapproving the
spontaneous theory.
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Louis Pasteur (1882-1895)
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• Pasteur experiment to disapprove spontaneous generation theory
Images: Studyblue
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• Devise methods and principles that led to
isolation of pure bacterial cultures. Good
for laboratory experiments!
• He rigorously validate the caused of
disease from microorganism.
• His postulates are still utilised and are
cornerstone for the study in bacteriology.
• Discover the cause of TB (tuberculosis) in
which at his time caused 1 in 7 death of
human populations.
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Robert Koch (1843-1910)
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1. The microorganism or other pathogens must be present in
all cases of disease.
2. The microorganism or pathogens can be isolated from the
diseased host and grown in pure culture plate.
3. The microorganism or pathogens from the pure culture
must cause the disease when inoculated into a healthy,
susceptible animals.
4. The microorganism or pathogens re-isolated from the new
host must show the same pathogenicity as the original
isolation when culture and inoculated into other healthy and
susceptible animals.
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Koch’s postulates
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1. The microorganism need to be cultured and grown in pure
culture.
2. At most time, wild type pathogens requires complex
nutrients which cannot be supplied within a culture plate.
This limitation can cause pathogens of interest to die.
3. Slow growing pathogens have slim chances in growing on a
culture plate against other fast growing ones.
4. Organism that do not grow in selected media will fail.
5. Did not consider microevolution in which at that time, the
term was not discovered yet.
6. Selected media might not be compactable with pathogen in
which causes the pathogen to die.
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Major limitations of Koch’s postulates.
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• Was first develop by Fannie & Walter Hesse (agar media) and
Richard Petri (petri plate).
• Originally, gelatin was first used instead or agar but was later
discarded as gelatin is easily degradable.
• Uses aseptic technique to prevent interference of other
microorganism.
• Technique in pure culture isolation. By third streak, only microorganism of
interest will be seen on the culture surface.
Images: shmoop.com
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Pure culture isolation
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Milestone in Microbiology
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• There are a lot of diversity
out there in the world.
• Basically, the population of
microorganism are a lot
more than any human
population could ever
compete with.
• Know that microbial world
grown in pure culture do
not necessarily represent
the wild population.
• Microbes exist and operate
in diverse community.
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Microbial world
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• Microbes are first living being that create the world where
other organism can live in.
• Microbes are foundation of life as well as biology.
• Started out with prokaryotes
and slowly emerging to what it
is today.
• Example:
 Chloroplast is product of
degenerate cyanobacteria!
http://www.youtube.com/watch?v=8SgnnV
8nV9g
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World created by microbes.
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• Microbes play crucial roles in the world we life today. They are
important in;
1. Food industry (ie: Preservation, Fermentation)
2. Agricultures (ie: Mychorrhizae)
3. Environments (ie: Nitrobacteria fixation)
4. Medicine and Pharmaceutical (ie: Penicillin)
5. Internal flora of our body (ie: E. coli)
6. Biotechnology (ie: Fuel generated form bacteria)
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Importance of microbes.
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