The document provides a history of microbiology from ancient beliefs in spontaneous generation to modern discoveries confirming the germ theory of disease. It describes key early microscopists like Hooke, Leeuwenhoek, and van Helmont and experiments by Needham, Spallanzani, and Pasteur disproving spontaneous generation. It also summarizes Robert Koch's experiments demonstrating that specific bacteria cause specific diseases and his postulates for identifying pathogenic microbes. The "Golden Age of Microbiology" from 1857-1914 is highlighted, featuring discoveries like antibiotics, vaccines, and staining techniques.

1. HISTORY OF MICROBIOLOGY
SPONTANEOUS GENERATION
GERM THEORY
UJJWAL SIROHI
Ph. D research scholar
@sirohiujjwal

2. microorganism exists
Lucretious
(about 98-55 BC)
Girolamo Fracastoro
(1478-1553)

3. 1590-1608
Hans & Z. Jansen
• first useful compound
microscope
• associated with the invention
of the first optical telescope

4. Robert Hooke(1665)
He examined a piece of dried
cork
Coined the term “cell”
Published first drawing of
microorganism in
„Micrographia‟

5. The belief of spontaneous generation
 Living organisms can originate from non-living
sources.
 Jan Baptista van Helmont(1580-1644)

6. Francesco Redi(1668)
 Italian physician
 Carried out a series of experiment
on decaying meat and its ability to
produce maggots spontaneously.

7. 1 2
3
Maggot eggs
Maggoteggs
Conclusion:
 Generation of maggots resulted from the
presence of fly eggs,
 meat did not spontaneously generated
maggots as previously believed.
but…

8.  But then, Leeuwenhoeke discovery renewed the
controversy.

9. Antonie van Leeuwenhoek(1632-1723)
In 1673 : observe living free-living
cells & called them animalcules.
First to describe sperm cells of
humans, dogs, rabbit, frogs, fish
& insects
Observed movement of blood cells
in mammals of mammals, birds,
amphibians & fishes.

11.  Supporters of spontaneous generation pointed out
that boiled extract of meat will give rise to
microorganism after sitting for a while.

12.  English priest & botanist.
 He concluded: organic matter contain
vital forces that could confer the
properties of life on non-living matter
John Needham (1748)

13. Lazzaro Spallanzani (1769)
 Italian priest
 Improved Needham experiment

14.  Spallanzani concluded:
 Air carried germs to the culture medium,
 external air might be required for the growth of
animals already in the medium.
------------

15. critics
Regardless of Spallanzani experiment critics stated:
“heating the air in sealed flask destroyed its ability
to support life”

16. BIOGENESIS

17. Louis Pasteur
 A french biologist,
microbiologist and
chemist renowned for his
discoveries of the
principles of
vaccination, microbial
fermentation and
pasteurization.

18. the germ theory
 Louis Pasteur worked in the middle and
late 1800s. He performed numerous
experiments to discover why wine and
dairy products became sour, and he
found that bacteria were to blame.
 Pasteur called attention to the importance
of microorganisms in everyday life and
stirred scientists to think that if bacteria
could make the wine “sick,” then
perhaps they could cause human illness.

20. Revolutionary flask(1861)
SWAN NECK FLASK
STERILE LIQUID COULD BE EXPOSED ONLY TO THE
AIR BUT NO OUTSIDE PARTICLES (DUST OR BACTERIA)
COULD GET PAST THE CURVE IN THE FLASK’S NECK

21. The experiment

22.  This demonstrates that microorganisms do not
appear as a result of Spontaneous
Generation. Instead, they are introduced into
food through dust particles and other things
that happen to land on the food.
 Supported the theory of biogenesis.
 His work also encouraged the belief that
microorganisms were in the air and could cause
disease.
 Pasteur postulated the germ theory of
disease, which states that microorganisms are
the causes of infectious disease. (UNPROVEN)

23.  John Tyndall (1820-1893)
In 1877 demonstrated that dust did indeed carry
germs & that if dust was absent, broth remained
sterile even if directly exposed to air.
 Ferdinand Cohn (1828-98)
Discovered the existence of heat-resistant bacterial
endospores.

24. Robert Koch
 1876
 First to demonstrate the role of bacteria in
causing disease by the study of anthrax.(proved
germ theory)
 The German scientist provided the proof by
cultivating anthrax bacteria (Bacillus anthracis).
 He then injected pure cultures of the bacilli into
mice and showed that the bacilli invariably
caused anthrax.

25. Koch‟s experiment

26. Koch‟s postulates
Four criteria that were established by Robert Koch to
identify the causative agent of a particular disease,
these include:
 the microorganism or other pathogen must be present
in all cases of the disease,
 the pathogen can be isolated from the diseased host
and grown in pure culture,
 the pathogen from the pure culture must cause the
disease when inoculated into a healthy, susceptible
laboratory animal,
 the pathogen must be reisolated from the new host
and shown to be the same as the originally
inoculated pathogen.

27. THE GOLDEN AGE
1857-1914
 1857 - Pasteur described fermentation.
 1861- Disproved spontaneous generation.
 1867- Lister publishes on antiseptic surgery.
 1876- Telephone
 1877- Koch‟s postulates. (germ theory)
 1879- Bulb
 1880- Laveran discovered Plasmodium
(malaria)

28.  1881- Anthrax vaccine by Pasteur.
 1882- Koch discovered cause of TB.
 1884- Autoclave & Gram Stain.
 1885- Rabies vaccine by Pasteur,
 Escherich discovered E. coli
 1887- Richard Julius Petri
 1889- Beijerinick isolates root nodule bacteria &
in1899- proves virus causes tobacco mosaic disease.

29. 1903- Aircraft
 1903- Antibodies
 1911- Rous (viruses can cause
cancer)
 1914 WORLD WAR I
 1915-17 -bacterial viruses by
D‟Herelle & Twort

30.  1923: 1st edition of David Bergey‟s Manual
 1928: Griffith‟s transformation
 1931: Photosynthetic bacteria
 1933: Ruska‟s electron microscope
 1953: DNA double helix
 1955: F factor plasmid (Jacod & Wollman)
 1961: lac operon (Jacob & Monad)
 1970: Amber & Smith (RE)
 1977: Woese divided Procaryotes into Bacteria
& Archaea
 1980: STM & computers

31.  1983-84: Mullis (PCR technique)
 1995: Chicken pox vaccine approved(USA)
 1997: Largest bacteria (Thiomargarita
namibiensis)
 2006: RNAi
 2009: GFP

32. New type of virus found in the ocean
 The unusual characteristics of these abundant, bacteria-
killing viruses could lead to evolutionary insights.
 Date: January 24, 2018
 Source: Massachusetts Institute of Technology
 Summary: Researchers have identified a new type of
virus that is abundant in the world's oceans but has
escaped detection until now. The unusual characteristics of
these bacteria-killing viruses could lead to evolutionary
insights, the researchers report in a new study.

33. references
 Cliffs Notes
 Science Daily
 Prescott(7th edition)
 R. C. Dubey microbilogy
 wikipedia

34. Thank you
 Presented by Ujjwal Sirohi