Microbiology Notes

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* Microbiology: Study of microorganisms

Most microorganisms are pathogenicFalse
The majority of bacteria are harmless True
Total number of bacterial species: about 10 million to a billion

What is a microorganism?
An organism or virus too small to be seen without a microscope. (Smaller than 0.5 mm) Ex: Bacteria, Fungi, Protozoa, Algae, and Viruses

Microbiom: collection of microbes
Human cells vs. Microbial cells = 1:10

Which statement about Michaelangelo is not correct?
A. He was an Italian sculptor, painter, architect, poet and engineer B. His masterpiece sculptor “David”, was made between 1501 and 1504 C. He was a French sculptor and poet
D. Created the famous fresco on the ceiling of the Sistine Chapel in Rome

Branches of Microbiology
Medical Microbiology
Industrial Microbiology
Environmental Microbiology
Agricultural Microbiology
Legumes +N2-fixing microorganisms
Microorganisms have important role in cycling plant nutrients (N, P, C, S) Cattle production depends on rumen microorganisms

Biotechnology
Food production (Dairy products (ogurt, cheese) sauerkraut, pickles, sausage, bread, beer, wine etc.) Bioremediation (detoxification by use of microorganisms
Genetic Engineering (manipulation of genes in order to create new products)

* Who started Microbiology?
Antoine van Leeuwenhoek a Dutch merchant
The first person to see microbes as being ALIVE!
Father of bacteriology
*
* What Leeuwenhoek could see?
Different shapes of bacteria
Red blood cells, spermatozoa, plant and animal cells
Magnification of his microscope was 32X

Robert Hooke’s Microscope Compared to Leeuwenhoek’s
Robert Hook introduced the compound microscope
(objective lens + ocular lens)
Robert Hook (1665) reported that the smallest biological structural unites were “little boxes”-cells CELL THEORY- all living things are composed of cells

Golden Age of Microbiology (1830-1900)
Scientists searched for answers to the following questions:
Is spontaneous generation of microbial life possible?
What causes fermentation?
What causes disease?
How can we prevent infection and disease?

Is spontaneous generation of microbial life possible?
Aristotle proposed spontaneous generation-living things can arise from non-living matter Toads and snakes could be born of moist soles
Maggots could arise from corpses

Francesco Redi’s Experiment, 1670s
Flies with meat

1765 Lazzaro Sallanzani
conducted experients to disprove the doctrine of spontaneous generation biolied infusion, hermetically sealed the container. Nly a small crack in the neck was sufficient to allow penetration and development of “animalcules” in the infusion. Nicholas Appert patented his invention and established a business to preserve a variety of food in sealed bottles-canning

Finally!
Arguments about spontaneous generation resolved by Louis Pasteur Read about Louis Pasteur’s experiment

How he really did it?
Pasteur’s S-shaped flask kept microbes, but let in (Swan Neck Flask)

Joseph Meister
First person to be treated by Louis Pasteur against rabies

Pasteur’s Discoveries
Performed the most convincing experiment disproving the theory of spontaneous generation Role of yeast in alcohol fermentation
Devised the process of pasteurization and basis of aseptic techniques Disease of vine-cold be prevented by heating the wine for a short time to a temp of 55-60 degrees Celsius The first preventive treatment for rabies

What causes disease?
Pasteur developed germ theory of disease, but had no proof…began working on Anthrax, but could not get a cure

Robert Koch
Studied causative agents of disease
Gave the first proof that bacteria causes disease (by isolating the anthrax bacillus in pure culture)-germ theory of disease Perfected the technique of isolating bacteria in pure culture-solid media-boiled potato Discovered Mycobacterium tuberculosis-the organism causing the tuberculosis. Tuberculin-substance...
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