History of Microbiology 2

Let us study the next era i.e. the Golden Era in the history of Microbiology.

Golden Era- 

• Period between 1865 and 1882
• Foundations of the new science were laid
• The pioneer work Louis Pasteur , Robert Koch and Joseph Lister during this period was noteworthy.

Contributions of Louis Pasteur

• Louis Pasteur was the great pioneer in the studies of fermentation
• He showed that yeast is required to convert sugar to alcohol.
• He showed that specific organisms bring about different fermentation.
• He eventually convinced the world that fermentation process is a result of microbial activity.
• He discovered that the spoilage of beer and wines lead to the growth of unwanted micro-organisms.
• He developed a method to remove undesirable microbes from juice without affecting its quality.Heating the juice for half an hour at 62.8 C did the job. This Technique is known as pasteurization.
• This technique is now used widely in the wine and milk industry.

Germ Theory of Diseases

• According to Germ theory , Germs are responsible for a disease and not the inert matter.
• This theory ends the theory of spontaneous generation.
• Louis Pasteur was in favor of this theory.
• Robert Koch also was in the favor of same and he gave four postulates-

1.  A specific organism must be present in association with a given disease.
2. The organism must be isolated and grown in pure culture.
3. The isolated organism must be able to cause the same disease if a healthy susceptible animal is inoculated with it.
4. It must be possible to recover the organism from the animal in which the disease has been induced.

• Robert Koch also isolated and studied Bacillus Anthrasis , Vibrio Cholerae and Mycobacterium Tuberculi.

Pure Culture Concept

• A culture that consists of a single kind of micro-organisms , regardless of the number of individuals , in an environment free of other living organisms is called a pure culture.
• Fanny Hesse was the first to introduce Agar as a solidifying Agent.
• Robert Koch was the first to make Solid Media.

Development of Agricultural Microbiology

• Sergei Winogradsky opened the field of soil microbiology in last 1800's.
• He with beijerinck developed the technique of "Enrichment culture".
• The credit for establishing the role of micro-organisms in transformation of nitrogen and sulphur also goes to both of them.
• In 1888, Hellriegel and Wilfarth showed the mutualistic symbiosis between bacteria and the leguminous plants like clover.
• Beijerinck founded the free-living nitrogen fixing bacteria Azotobacter and described its usefulness in promoting soil fertility.
• The tobacco mosaic virus was isolated in crystalline form by Wendell m.Stanley and John H.Northup for which they were awarded with noble prize.

Development of medical microbiology 

• Louis Pasteur's Role- 

1. He discovered many disease causing pathogens in human.
2. He developed Vaccines for Cow Pox , Anthrax and Rabies.

• Joseph Lister's Contribution- 

1. Used carbolic Acid as Disinfectant Successfully in surgical Dressings.
2. He showed that it could also be used to clean postoperative wounds.
3. He is known as 'Father of Antiseptic Surgery' .

• Some scientist's and their discoveries-

1. Hensen - Leprosy Bacterium(Mycobacterium Leprae)
2. Ogston - Staphylococcus(Causes Abscesses)
3. Edwin Klebs and Frederick Loeffler - Diptheria Bacillus(CoryneBacterium diptheriae)
4. Shibasaburo Kitasato - Clostridium Tetani and Pasterulla Pestis
5. Emil Von Behring - Vaccine for Tetanus and also Serum therapy
6. Elie Metchnikoff - Phagocytosis of leucocytes
7. August Von Wassermann - Widal test for typhoid and wassermann test for syphillis

Discovery of viruses

• Beijerinck coined the term 'Virus'.
• River proposed criteria for viral diseases which were similar to Koch's postulates.They are as follows-

1. The virus must be present in the infected host cell or in its other components ,at the time of disease.
2. filtrate of such infectious material must not contain any other visible microbes, cultivable on synthetic media invitro, such filtrates when injected to susceptible experimental host (Plant or Animal) must produce the like disease and the other viral counter products.
3. Similar filtrate from these experimental hosts must transmit the same disease. 

So here we studied the discoveries in Golden era in very short and precise manner and will study further in the next part. I had discussed only those points which were important from my point of view.

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