Intro Flashcards
What are Stromatolites?
One of the first microorganisms on the planet
Identified in rock formations in Australia (Sharkbay)
Three billion years old
Laminated rock formed by layers of Cyanobacteria (Photosynthetic bacteria)
Changed the atmosphere to make it respirable for aerobic life
Paved the way for aerobic life
Describe the contribution to microbiology made by Robert Hooke (1635 – 1703)
Architect, astronomer, mathematician and natural philosopher
English philosopher played important role in the scientific revolution
1665 first scientific exploration with a microscope (beyond naked eye) called “Micrographia”
Although the existance of creatures too small to be seen by the naked eye had long been suspected their discovery was linked to the invention of the microscope.
Did this by inverting a telescope
Many disputes with competitors including Isaac Newton over gravity
The beginning of microbiology
Hookes Law of Elesticity which states that, for relatively small deformations (change in shape) of an object, the displacement or size of the deformation is directly proportional to the deforming force or load
F= Kx
Describe the contribution to microbiology made by Robert Hooke: Micrographia (1665)
How did his microscope work?
Hooke coined the term “cell” from describing biological organisms
Resemblance of plant cells to individual units of honeycomb
Illustration of insects and plants as seen through microscopes (magnifying glasses)
Captured the public’s imagination
- He used a kerosene lamp and a very polished dish that focused intense light onto a sample. With a series of different lenses he got an in depth view
Micrographia (1665)
4 page foldout of the household flea
Showed the world beyond what you could see with the naked eye
Describe the first description of a microorganism by Hooke
Hooke looked at mould growing on the surface of leather
Termed it Micology – he thought he was drawing a plant
Desribe the contribution to microbiology made by Anton van Leeuwenhoek (1632 – 1723)
Dutch lensmaker – pioneer in microscopic lense making
The Father of Microbiology
First to comprehensively describe microorganisms
Called unicellular organisms “Animacules” (from Latin animalculum = tiny animal)
He observed muscle fibres, bacteria (1676), spermatozoa, and blood flow in capillaries
How do you use van Leeuwenhoek’s Microscope?
What did he famously use it for?
The primitive microscope:
- Base plate goes up against your cheek
- Shut one eye and look through the tiny aperture
- sample mounted at the end of the pin
- He took a sample of plaque from his teeth
- Viewed it under his microscope
Published his findings of the different shapes and movements of what he saw and called them animalcules
Describe the contribution to microbiology made by Louis Pasteur (1822 – 1895)
Mechanism of alcohol fermentation, a biological process by yeast
Theory of Spontaneous generation about bacteria that spontaneously emerge and putrify substances
Food putrefaction: Whether organisms were from the air or spontaneous formation from non-living materials?
Hypothesised sterility by heat
Sealed flask remained sterile if microorganisms came from outside they would not affect the sterile contents
spontaneous generation needs air
Pasteur (Swan-neck flask experiment)
Describe Pasteur’s Experiments with Swan-necked Flasks
- Produced surgary and starchy mixture
- Poured the liquid into a bottle neck flask
- Neck of the flask drawn out by bunsen flame to create the swan neck
- Boiled liquid inside the flask
- steam escaped via the aperture
- If the flask was left upright, the liquid does not putrify and remains sterile for a long time (dust and microorganisms trapped in bend)
- If the flask is tipped, liquid putrefies (microorganism laden dust contacts sterile liquid)
What did Pasteur do for us?
Pasteurization
Vaccine for anthrax
Vaccine for fowl cholera
Vaccine for rabies
1st administered rabies vaccine for humans
Previously fatal
Joseph Meister bitten by rabid dog and pasteur injected him with rabies vaccine and he surviced (1885), Jean-Baptiste Jupille next person injected with the vaccine
Within a year, thousands had been vaccinated
What contribution to microbiology did Robert Koch (1843 – 1910) make?
Established Germ theory of disease
Discovered the causative agents of bacterial diseases (inc. TB)
Study of anthrax he identified that any organism that had Bacillus anthracis in their blood. He didnt know if this microorganism was the result of the antrax or the cause-
Always present in the blood of an animal succumbing to the disease but was it the cause or a result of the disease?
Kochs postulates allows us to establish this
Describe the development of Koch’s Postulates
The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
The microorganism must be isolated from a diseased organism and grown in pure culture.
The cultured microorganism should cause disease when introduced into a healthy organism.
The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
Give a summary of Summary of Koch’s Postulates
- The suspected pathogen must be present in all cases of the diesase and absent from healthy animals
- The suspected pathogen must be grown in a pure culture
- Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal
- The suspected pathogen must be reisolated and shown to be the same as the original
Koch and Tuberculosis (TB)
- In 1881, 1 in 7 deaths were attributed to TB
- Suspected to be an infectious disease
- Causative agent discovered by Koch: Mycobacterium tuberculosis
- Koch developed a method of staining the waxy bacteria (Acid-fast staining)
- Koch used blood serum to culture pure M. tuberculosis
- Used this to infect guinea pigs who succumbed to TB
- Reisolated M. tuberculosis, able to infect healthy guinea pigs
Describe the contribution to microbiology made by Ferdinand Cohn (1828 – 1898)
Founder of the field of bacteriology
He was a Botanist and very good at taxonomy
He believed bacteria were members of the plant kingdom
First to classify bacteria into 4 groups based on shape:
Sphericals,Short rods,Threads,Spirals
Discovered Bacillus, an endospore producing bacteria meaning it is resistant to heat heat (found all over our body)
Described the lifecycle of an edospore producing bacteria
How harmful are infectious diseases to society?
Harmful to society in various ways
Infectious diseases kill more people worldwide than cancer and heart disease combined
Infectious diseases are the leading cause of death in the world.
9.5 million people die each year
In the past 50 years more people have died from malaria, TB and AIDS than in all wars.
Evolution of new, virulent and resistant infectious agents
Fedinand Cohn: How are bacteria classified?
