Introductory Microbiology Bryan Paul University of Alberta, Canada [email protected] 1.
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Transcript of Introductory Microbiology Bryan Paul University of Alberta, Canada [email protected] 1.
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Introductory Microbiology
Bryan PaulUniversity of Alberta, Canada 1
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Objectives
1. Know the history of emergence in microbiology2. 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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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)
Figure showing his microscope and his observationImages: history.org and Kunal Bheecarry
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Spontaneous generation Theory1. 384-55BC
• 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. 4
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2. 1626 – 1799
• Francesco RediNotice that cheesecloth over meat did not induce the emergence of
maggotsDisapprove spontaneous generation theory
• John NeedhamObserved 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 microbesDisapprove spontaneous generation theory.
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Louis Pasteur (1882-1895)
• 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 processdetermining the nature of diseasePasteurisation process And ultimately disapproving the
spontaneous theory.
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• Pasteur experiment to disapprove spontaneous generation theoryImages: Studyblue 7
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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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Koch’s postulates1. 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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Major limitations of Koch’s postulates.
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. 10
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Pure culture isolation• 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.
11• 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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Milestone in Microbiology
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Microbial world• 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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World created by microbes.
• Microbes are first living being that create the world where other organism can live in.
• Microbes are foundation of life as well as biology.
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• 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=8SgnnV8nV9g
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Importance of microbes.• 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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