History of Microbiology Flashcards
What allowed the scientific advancements of microbiology?
The invention of the microscope.
What was Robert Hooke’s contribution to microbiology?
- Invention of the microscope
- Able to see fruiting bodies on mold (fungi i.e. eukaryotic cells which are much larger than prokaryotic cells)
What was Antoni van Leeuwenhoek’s contribution to microbiology?
- Built a more refined microscope than Robert Hooke
- First to see bacteria (which he termed “animalcules”)
What were the major unanswered questions following the discovery of “animalcules”?
1) Where do they come from? Spontaneous generation or biotic sources?
2) Are they responsible for infectious disease
What were the major theories concerning the orgin of animalcules?
1) Spontaneous generation: animalcules arise spontaneously from non-living material
2) Theory of biogenesis: living organisms arise from living organisms
Who are the major contributors to the defeat of spontaneous generation?
- Lazzaro Spallanzani
- Louis Pasteur
What was Lazzaro Spallanzani’s contribution to microbiology?
Experiment:
In this experiment, beef broth is boiled and allowed to cool
- Flask is teeming with animalcules
The same experiment is done with a rubber stopper
- Broth remained sterile
- No animalcules; no spontaneous generation
Experiment repeated with a cotton plug
- Because spontaneous generation proponents said it required fresh air
- Broth still remained sterile
- Hence, boiling was assumed to interfere with spontaneous generation
What was Louis Pasteur’s contribution to microbiology?
- Disproved the theory of spontaneous generation
(a) A flask with a long neck is bent. Spallanzani’s experiment was repeated with this flask.
(b) The microorganisms were trapped in the bent part of the neck. The broth remained sterile.
(c) If the flask is tipped, the broth is in contact with the microorganisms and the liquid putrefies.
Hence, animalcules come from other animalcules.
What was John Tyndall’s contribution to microbiology?
- He discovered endospores by repeating Pasteur’s experiment with hay infusion
Why is it that Pasteur’s experiment did not work with hay infusion? (i.e. broth swarmed with microorganisms)
This is due to endospores.
When a stress is introduced (e.g. boiling), the hay infusion bacteria produces endospores (survival capsules).
In the presence of a nutrient environment, there is germination and endospores become vegetative cells.
What was Edward Jenner’s contribution to microbiology?
Observation: people milking cows never develop small pox
Cows can develop cowpox (not deadly, just unsightly
- The daughters milking cowpox cows didn’t develop small pox
Jenner removed the exudates from a cow and injected it in an 8-year old boy.
- The boy lived while other males of the family died
Jenner is credited for generating the 1st vaccine (for small pox).
What was Ignaz Semmelweis’s contribution to microbiology?
Observation: high mortality rate of women giving birth in hospitals (about 50%)
- Most died of puerperal (childbed) fever
- Only 12% of mothers giving birth at home with midwives died
- Reason: physicians didn’t wash hands between patients
Semmelweis instituted mandatory hand washing (at his hospital)
- Mortality rates dropped to 10%
What was Joseph Lister’s contribution to microbiology?
Specialist in surgical and wound infections
Credited with the institution of antiseptic practices
- For treating instruments, dressings etc. used for surgeries.
What was Koch’s contribution to microbiology?
He proved that bacteria caused infectious disease.
Describe Koch’s experiment
- Drew blood from an infected mouse (blood teeming with bacteria).
- Blood was injected in another mouse.
- The injected mouse died.
- The experiment was repeated with 20 mice.
- Isolated a culture of the bacteria and injected in a new mouse.
- This mouse died also.
