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History of Microbiology

Microbiology is the study of microorganisms too small to be seen clearly without a microscope. The history of microbiology began with early observations of microbes in the 17th century. Key figures like Antony van Leeuwenhoek, Louis Pasteur, Joseph Lister, and Robert Koch helped prove germ theory and establish microbiology as a science through their experiments showing microbes cause disease. Major advances included developing pure culture techniques, discovering antibiotics like penicillin, and learning microbes play important roles in environments and ecosystems.

Science◦
UNIVERSITY OF ALLAHABAD DEPARTMENTOF BOTANY TOPIC: HISTORYOF MICROBIOLOGY Submitted to : Prof. H. K. Kehri
Introduction • Microbiology often has been defined as the study of organisms and agents too small to be seen clearly by the unaided eye—that is, the study of microorganisms. • Objects less than about one millimeter in diameter cannot be seen clearly and must be examined with a microscope, microbiology is concerned primarily with organisms and agents this small and smaller. • Monstrous bacteria- Thiomargarita and Epulopiscium • Microorganisms are diverse group, relatively simple in their construction, lacking highly differentiated cells and distinct tissues.
• On the basis of rRNA studies Carl Woese in 1970s divided organisms into 3 domain: i) Bacteria ii) Archaea iii) Eukarya
HISTORY OF MICROBIOLOGY  DISCOVERY ERA : • Roman philosopher Lucretius (about 98–55 B.C.) and the physician Girolamo Fracastoro (1478–1553) suggested that disease was caused by invisible living creatures.
• In 1665, the first drawing of a microorganism was published in Robert Hooke’s Micrographia. Antony van Leeuwenhoek (1632–1723) • He constructed simple microscopes composed of double convex glass lenses held between two silver plates • His microscopes could magnify around 50 to 300 times • In 1676, he observed and described micro -organisms such as bacteria and protozoa as “Animalcules”.
 TRANSITION PERIOD : • Aristotle (384–322 B.C.) thought some of the simpler invertebrates could arise by spontaneous generation. • Italian physician Francesco Redi (1626–1697), who carried out a series of experiments on decaying meat and its ability to produce maggots spontaneously. John Needham (1713–1781) reported the results of his experiments on spontaneous generation. • He proposed that tiny organism(animalcules) arose spontaneously on the mutton gravy
Lazzaro Spallanzani (1729-1799) • He demonstrated that air carried germs to the culture medium. • He showed that boiled broth would not give rise to microscopic forms of life.  GOLDEN ERA (1857-1914): Agostino Bassi (1773–1856) first showed a microorganism could cause disease when he demonstrated in 1835 that a silkworm disease was due to a fungal infection. • He also suggested that many diseases were due to microbial infections. • In 1845, M. J. Berkeley proved that the great Potato Blight of Ireland was caused by a water mold. • 1853, Heinrich de Bary showed that smut and rust fungi caused cereal crop diseases.
Louis Pasteur (1822-1895) • Father of Medical Microbiology. • He disapproved the theory of Spontaneous generation by performing an experiment with swan neck-shaped tube. • In 1897, he suggested that mild heating at 62.8⁰C for 30 min was enough to destroy the undesirable organisms without ruining the taste of the product, called as Pasteurization. • He invented the process of fermentation and also developed effective vaccines against rabies and anthrax. • He investigated pebrine disease of silkworm and showed that disease was due to a protozoan parasite.
Pasteur’s experiment to disapprove Theory of Spontaneous Generation
Joseph Lister (1827–1912 • Developed a system of antiseptic surgery designe to prevent microorganisms from entering wounds. • Instruments were heat sterilized, and phenol was used on surgical dressings and at times sprayed over the surgical area. John Tyndall (1820–1893) • dealt a final blow to spontaneous generation in 1877 by demonstrating that dust did indeed carry germs and that if dust was absent, broth remained sterile even if directly exposed to air. German botanist Ferdinand Cohn (1828–1898) • discovered the existence of heat-resistant bacterial endospores.
Robert Koch (1843–1910) • He demonstrated the role of bacteria in causing disease. • Koch injected healthy mice with mater -ial from diseased animals, and the mice became ill. • His criteria for proving the causal relationship between a microorganism and a specific disease are known as Koch’s postulates • He reported that tuberculosis was caused by a rod-shaped bacterium, Mycobacterium tuberculosis.
Demonstration of Koch’s postulates
• Koch developed culture media using meat extracts and protein digests because of their similarity to body fluids. He first tried to solidify the media by adding gelatin. • Since gelatin was not an ideal solidifying agent because it can be digested by many bacteria and melts at temperatures above 28°C. Fannie Eilshemius Hesse (1850-1934) • Suggested the use of agar as a solidifying agent as it was not attacked by most bacteria and did not melt until reaching a temperature of 100°C. Richard Petri (1887) • He devised petri dish used for solid culture media. Charles Chamberland (1851–1908), constructed a porcelain bacterial filter in 1884.
Dimitri Ivanowski and Martinus Beijerinck • Used the filter to study tobacco mosaic disease. • They found that plant extracts and sap from diseased plants were infectious, even after being filtered with Chamberland’s filter. • Because the infectious agent passed through a filter that was designed to trap bacterial cells, the agent must be something smaller than a bacterium. • Beijerinck proposed that the agent was a “filterable virus.” • Emil von Behring (1854–1917) and Shibasaburo Kitasato (1852–1931) injected inactivated toxin into rabbits, inducing them to produce an antitoxin, a substance in the blood that would inactivate the toxin and protect against diphtheria. • Elie Metchnikoff (1845–1916) discovered that some blood leukocytes could engulf disease-causing bacteria. He called these cells phagocytes and the process phagocytosis
 MODERN ERA : • In 1929, Alexander Fleming discovered that the fungus Penicillium produced what he called penicillin, the first antibiotic that could successfully control bacterial infections. Russian microbiologist Sergei Winogradsky (1856–1953) made many contributions to soil microbiology • discovered that soil bacteria could oxidize iron, sulfur, and ammonia to obtain energy, • many bacteria could incorporate CO2 into organic matter much like photosynthetic organisms do. Martinus Beijerinck (1851–1931) • Isolated the aerobic nitrogen-fixing bacterium Azotobacter, a root nodule bacterium also capable of fixing nitrogen (later named Rhizobium), and sulfate-reducing bacteria.