Major Milestones in Microbiology

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@VET GUIDE

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Major Milestones in Microbiology

• 1500 B.C. Ancient Egyptians ferment cereal grains to make beer.
• 1546AD Italian physician Girolamo Fracastoro suggests that invisible organisms may cause disease.
• 1676 Antony van Leeuwenhoek observes bacteria and protozoa using his homemade microscope.
• 1796 Edward Jenner introduces a vaccination procedure for smallpox.
• 1838-39 Mathias Schleiden and Theoder Schwann independently propose that all organisms are composed of cells, the basic unit of life.
• 1847-50 Physician Ignaz Semmelweis demonstrates that childhood fever is a contagious disease transmitted by physisians to their patients during childbirth.

Major Milestones in Microbiology

• 1853-54 John Snow demonstrates the epidemic spread of cholera through a water supply contaminated with human sewage.
• 1857 Louis Pasteur demonstrates that yeast can degrade sugar to ethanol and carbon dioxide and multiply in the process
• 1867 Joseph Lister publishes the first work on antiseptic surgery, beginning the trend toward modern aseptic techniques in medicine.
• 1881 Robert Koch introduces the use of pure culture techniques for handling bacteira in the laboratory.

Walter and Fanny Hesse introduce agar-agar as a solidifying gel for culture media

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Major Milestones in Microbiology

• 1882 Koch identifies the causative agent of tuberculosis.

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• 1884 Koch states Koch’s postulates

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• Elie Metchnikoff discovers phagocytic cells and thus begins the study of immunology.

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• Hans Christian Gram devises the gram stain technique, which differentiates bacteria.

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• 1887 Iulius Petri, a German bacteriologist, adapts two plates to form a container for holding media and culturing microbes – petri dish.

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• 1908 Paul Ehrlich develops the drug salvasan to treat syphilis thereby starting the use of chemotherapy to treat diseases.

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Major Milestones in Microbiology

• 1911 F. Peyton Rous discovers that a virus can cause cancer in chickens (Rous sarcoma virus)

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• 1928 Frederick Griffith discovers genetic transformation in bacteria, thereby raising a key question in genetics: What caused the transformation?
• 1929 Alexander Fleming discovers and describes the properties of the first antibiotic, penicillin.
• 1944 Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrate that Griffith’s transforming principle is DNA.
• Joshua Lederberg and Edward Tatum demonstrate that DNA can be transferred from one bacterium to another.
• 1953 James Watson, Francis Crick, Rosalind Franklin, and Maurice Wilkins determine the structure of DNA.
• 1971 Theodor Diener demonstrates the fundamental differences between viroids and viruses.

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Major Milestones in Microbiology

• 1973 Herbert Boyer and Stanley Cohenn, using plasmid, are the first to cone DNA.
• 1975 Cesar Milestein, Georges Kohler, and Niels Kai Jerne develop the technique for making monoclonal antibodies
• 1976 Michael Bishop and Harold Varmus discover the cancer-causing genes called oncogenes in viruses, and find that such genes are present in normal tissues.
• 1982 Stanley Prusiner isolates a protein from a slow disease infection and suggests that it might direct its own replication. He suggests the agent be termed prion.
• 1983 Luc Montoagnier of France and Robert Gallo of United States independently isolate and characterize the human immunodeficiency virus (HIV) that causes AIDS.
• Kerry Mullis invents the polymerase chain reaction (PCR)
• 1993 Three ”new” diseases appear in the United States, emphasizing that emerging diseases are a continued threat to people’s health.

Major Milestones in Microbiology

• 1994 The Food and Drug Administration approves the first genetically engineered food for human consumption, a slower-ripening tomato.
• 1995 The Food and Drug Administration approves the first protease inhibitor , a major weapon against the progression of AIDS.
• The first complete nucleotide sequence of the chromosomes of the bacterium is reported (Haemophilus influenzae).
• 1997 The first complete nucleotide sequence of all of the chromosomes of eukaryote is reported (yeast).

Louis Pasteur (1822-95)

• Principles (Techniques of Bacterial cultivation)
• Every alteration of either wine or beer depends on development of microorganisms.
• The microorganisms are brought by the ingredients or apparatus used in breweries.
• Whenever beer or wine contains no living organisms, it remains unchanged.

Louis Pasteur’s Contribution in Microbiology

1. Methods and techniques for cultivation of microorganisms.
2. Conclusive evidence for microorganisms in disease production.
3. Introduction of sterilization technique and development of steam sterilizer, Hot air oven and autoclave.
4. Studies on pebrine (silk worm disease), anthrax, chicken cholera and hydrophobia.
5. Live vaccine

�Robert Koch (1843-1910) �Father of medical microbiology�

• A German general practitioner, perfected bacteriological techniques and introduced methods for isolation of pure strains of Bacteria
• Introduced staining techniques

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Koch’s postulates

1. The organism should be constantly associated with the lesions of the disease.

2. The organism should be isolated from the lesion in the pure culture.

3. The isolated organism in pure culture when injected in susceptible animals should produce the disease.

4. From the lesions produced in experimental animals, the microorganism must demonstrated both in smear and culture.

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