Contributions of Louis Pasteur & Selman A. Waksman in microbiology.. Their discoveries for the development in the field of microbiology..

1. Contributions of Louis
Pasteur & Selman
A.Waksman
If you can do, you shall do; If you can’t do,
you must do

2. Louis Pasteur(1822-1895)
Chemistry professor in France
Disproved the spontaneous generation theory
Discovered that fermentation of fruits & grains resulting
alcohol ,was by microbes
Sorted different microbes giving different taste of wines
Selected a particular strain (yeast) for high quality wine

3. Louis Pasteur
Pasteur Institute, Paris

4. Louis Pasteur
Developed a method to remove the undesired
microbes from juice without affecting its quality.
Heating the juice at 62.80 C for 30 minutes
killed microbes (71.7-15 seconds).
This technique is known as pasteurization,
widely used in milk industries
Discovered the parasites (Protozoa) causing
pebrine disease of silk worm.

5. Louis Pasteur
Suggested that disease free caterpillars can eliminate the
disease
Isolated the anthrax causing bacilli from bloods of cattle,
sheep and human beings
Demonstrated the virulence(ability to cause disease) of
bacteria
Demonstrated the principle of immunization & he called
the attenuated cultures as vaccines (a term derived from
Latin Vacca meaning cow)
Developed vaccine( a killed or attenuated microbe to
induce immunity) against rabbits from the brain and
spinal cord of rabbit

6. Germ theory of disease
Bacteria are the cause of disease –reported
before Pasteur-but not proved
Verona reported that disease is due to some
invisible organisms
Pasteur work on –Pebrine disease of silk worm
Robert Koch work on Anthrax disease of cattle

7. Pasteur’s demonstration on immunization
During 1880, he isolated the bacterium causing chicken
cholera and arranged for a public demonstration.
Inoculated healthy chicks with his pure cultures.
The chickens failed to get sick and die.
He found that the cultures he used was several weeks old.
Some weeks later he repeated the experiments.
He used two groups of chickens and inoculated with fresh
cultures.
The chicken in second groups got sick and died and the first
group remained hale and healthy.

8. Vaccine for chicken cholera

9. He found that the bacteria could loose their
ability to produce disease i.e., virulence.
But this attenuated bacteria still retained their
capacity for stimulating the host to produce
substances i.e., antibodies, that protect against
subsequent exposure to virulent organisms

10. Development of rabies vaccine
Rabies (hydrophobia),a disease transmitted to people by bites of
dogs, Cats and other animals
A boy Joseph Meister was bitten by a mad wolf
He produced this disease in rabbits by inoculating the saliva from
mad dogs
He removed the brain and spinal cord from the infected rabbits,
dried, pulverized and mixed with glycerin
Injecting this mixture into dogs protected them against rabies
Joseph Meister was injected with same mix and he was saved after
several weeks

11. Rabies vaccine

12. Selman A.Waksman
American microbiologist
Isolated of Thiobacillus
thiooxidans (Waksman and
Joffe, 1922) as his most
important scientific
discovery before the
antibiotics

13. 1927 - Principles of soil Microbiology
In 1939 Waksman and his colleagues undertook a
systematic effort to identify soil organisms producing
soluble substances that might be useful in the control of
infectious diseases, what are now known as antibiotics
Within a decade ten antibiotics were isolated and
characterized.
Three of them with important clinical applications
actinomycin in 1940, streptomycin in 1944, and
neomycin in 1949.
Eighteen antibiotics were discovered under his general
direction.

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R.ABARNA
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