History of microbiology Flashcards
Discuss the era of abiogenesis
Aristotle (384-322 B.C) believed and taught that animals might generate spontaneously from soil, plants, or other unlike animals.
This Aristotelian concept of spontaneous generation (abiogenesis) was prevalent before late 1800
Discuss the era of assumption
During the thirteen century, Roger Bacon (1220-1292) postulated that invisible living creatures produce disease.
This suggestion was made again by Girolamo Fracastoro of Erona (1483-1553)
Anton von Plenciz in 1672 also made similar suggestion but with no proof.
Discuss the era of PURPOSIVE MICROBIOLOGY
Pasteur (1822-1895) and John Tyndall (1820-1893) performed different experiments that silenced the concept of abiogenesis
Louis Pasteur, discovered the process of fermentation through the manufacturing of wines and beer.
He discovered the process of microbes removal by holding juices at a temperature of 62.8 degrees celsius for half an hour- Pasteurization
Pasteur investigated ‘PEBRINE’ a silkworm disease that was ruining an important French industry. He isolated the parasite causing the disease. And suggested solution.
Pasteur next grew agent of anthrax from laboratory flasks after isolating them from the blood of animals that have died of the disease.
KOCH’S POSTULATES
He isolated Bacillus anthracis from the blood of cattle that had died of anthrax and injected them into other animals
The injected animals developed clinical symptoms of anthrax
From these experimentally infected animals he isolated microbes like those he had originally found in sheep that died of anthrax.
These series of observation led to the establishment of Koch’s postulates, which provided the guidelines to identify causative agent of an infectious disease.
Robert Koch (1843-1910), a physician, was about the same time busy with the anthrax problem in Germany.
Discuss the development of pure culture
Pure culture were first obtained by Joseph Lister in 1878 using serial dilutions in liquid media, providing a great boost in infectious diseases’ discovery
Based on the koch’s postulate, Robert Koch announced the discovery of the agents of tuberculosis and cholera
Pure cultures was largely used to identify the microorganisms responsible for many infections, certain fermentations, nitrogen fixation in the soil and other activities
While examining fluids that were undergoing a butyric acid fermentation microscopically, Pasteur discovered the anaerobic world
Discuss the discovery of immunity
Pasteur had a failed public demonstration of Kock’s postulates using pure culture of chicken cholera as a result of accidental use of old cultures in 1880
He repeated the experiment, using two groups of chickens: those with previous exposure were hale and hearty while those without got sick and died.
Discovery: bacteria could loose their virulence on growing old but stimulate host’s immunity
This explained the principle involved in Edward Jenner’s successful use of cowpox virus in 1798, to immunize people against smallpox.
Pasteur next applied the principle to the prevention of anthrax.
He called the attenuated cultures vaccines
This principle was later used by Pasteur in the preventive treatment against rabies
Pasteur and Koch’s recognition
The success of Pasteur and Koch brought honours and accolades from their appreciative countrymen.
Koch became Professor of Hygiene and Director of the institute for infectious diseases, which was founded for him at the University of Berlin.
France established the Pasteur institute in Paris in 1888.
To each of these men came scholars from all over the world and these students later carried the spirit and knowledge of Koch and Pasteur to America and throughout Europe.
Discuss the discovery of viruses
Infectious fluids were often tested for the presence of disease-producing bacteria by passing them through micro filters and considered free of the bacteria if the filtrate was no longer able to produce infection
In 1892, a Russian scientist, Iwanowsky found to his surprise that infectious extract from tobacco plants infected with mosaic disease after filtration was fully infectious when applied to healthy plants
This was confirmed by Beijerinck in 1898
Foot-and mouth disease was discovered by Loeffler and Frosch about 1898
Viruses of other animal diseases were later discovered
Discuss the era of antimicrobial chemotherapy
Began in 1935 with the discovery of the sulfonamides.
In 1940, it was demonstrated that penicillin, discovered in 1929, could be an effective therapeutic substance. In the next 25 yrs, research on chemotherapeutic agents centred largely those of microbial origin. (antibiotics).
The production of penicillin were followed by the development of streptomycin, tetracyclines, chloramphenicol, and many other agents. originally from filtrates of respective moulds.
Synthetic modification of previously described drugs has been prominent in the development of new antimicrobial agents.
Newer discoveries include
*the era of molecular biology which began suddenly in 1953 by J.D Watson and F.H.C Crick in nature proposing the structure of DNA.
*In the mid 1950s microbial biochemistry also set out in new directions to understand how the myriads of individual cellular reaction were efficiently and harmoniously controlled to accomplish biological functions.
In the mid- 1970s a series of discoveries ushered in a new and powerful set of capabilities known as recombinant DNA technology
This has been applied to a number of fundamental and practical biological questions like production of medically important proteins (e.g insulin, human growth hormones and factor VIII), and the improvement of industrial fermentations.
It holds almost certain promise for the production of other therapeutically useful proteins and fermentation products as well as for crops improvement and the detection and treatment of genetic defects in humans.
