Contributions of Louis Pasteur & Selman A. Waksman in microbiology

Contributions of Louis Pasteur & Selman A.Waksman

If you can do, you shall do; If you can’t do, you must do

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

Louis Pasteur

Pasteur Institute, Paris

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.

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

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

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.

Vaccine for chicken cholera

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

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

Rabies vaccine

Selman A.Waksman

American microbiologist

Isolated of Thiobacillus thiooxidans (Waksman and Joffe, 1922) as his most important scientific discovery before the antibiotics

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.

BYR.ABARNABTH-12-001

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