2. MICROBIOLOG
□ Study
Y
of Microbes –
too small to be
seen with naked
eye.
□ Less than 1mm in
diameter.
□ Some are visible to
the naked eye –
e.g.Bacterium
Epulopiscium,
filamentous
algae, bread
mould, mush
rooms etc.
Image : https://alchetron.com/Epulopiscium-fishelsoni
3. MICROBES
□ Extremely diverse group
• Bacteria ( Study of Bacteria -Bacteriology)
• Algae( Study of Algae -
Phycology)
Fungi ( Study of Fungi - Mycology)
•
• Viruses (Study of Viruses - Virology)
• Protozoa ( Study of Protozoa -
Protozoology)
5. THEORETICAL(PURE)
MICROBIOLOGY
• Study of occurrence
• Form
• Structure
• Classification
• Physiology
• Reproduction
• Heredity
• Variation and Evolution of
microbes
6. APPLIED
MICROBIOLOGY
□Exploitation of beneficial microbes
□Control the activities of harmful microbes
Types:
• MedicalMicrobiology– Study of role of
microbes in human & animal diseases.
• Agricultural Microbiology – Role of microbes
in plant diseases, soil fertility and spoilage of
agricultural products.
7. Microbiology- Utilisation of
• Industrial
microbes the production
bfoerverages,antibalicootihcos,licamino
of
acids,
organic acids –acetic acid, lactic acid, citric
acid etc.
• Food Microbiology – Role of microbes in
food spoilage, their prevention and to
increase the shelf life of various food
products ; production of cheese, butter,
fermented milk etc.
8. HISTORY OF
MICROBIOLOGY
• Microbes – discovered
in the late 17th century.
observed by
van
• First
Anton
Leeuwenhoek –
• A Dutch draper - Hobby
was lens grinding and
microscope making.
• Made 550 crude single
lens microscopes with
magnification of 50x –
10. Anton van Leeuwenhoek’s observation of
microbes
Image:
https://delftschoolmicrobiology.weblog.tudelft.nl/
11. • Leeuwenhoek examined rain water, saliva,
pepper decoctions, cork, leaves of plants ,
seminal fluid, scrappings of teeth etc.
• Portrayed several microorganisms and called
them ‘Animal cules’.
• Conveyed his findings in a series of letters to
the British Royal Society, London during the
mid 1670’s.
12. • Leeuwenhoek outlined the structural details
of Paramecium, Amoeba, certain filamentous
fungi, algae , bacteria etc.
• Scientists considered microbes only as
‘Curiosities of Nature’.
• Controversy regarding Spontaneous
generation (Abiogenesis) drew scientists to
explore the origin and nature of living things.
13. • Spontaneous generation(Abiogenesis)
A belief in ancient times that living organisms
could develop from non – living matter.
• Theory of Biogenesis – Living organisms
arise only from preexisting organisms.
14. Experiments to disprove
Abiogenesis
Redi’sExperiment (1688):
(Francesco 1626
R
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d6
i 97, Italian Physician)
Carried out a series of
experiments on decaying
meat and its ability to
produce maggots
spontaneously.
Image
https://fineartamerica.com/f
e
15. Redi placed meat in 3 jars
Jar 1 : Left open.
Flies laid eggs on meat -
which developed
into maggots .
Image
http://faculty.sdmiramar.edu/
16. Jar-2 : Covered with netting
• Flies laid eggs on the
netting – developed
into maggots on the
netting.
• Image http://faculty.sdmiramar.edu/
17. Jar-3 : Sealed
• No maggots developed
on meat.
• This experiment
proved that the
maggots developed
from fly eggs , not
from meat .
• Thus Redi
disproved the
theory of
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. Image
http://faculty.sdmiramar.edu/
18. Experiment of Louis
Pasteur
• Experiments in Swan –neck flasks - Disproved
the theory of Abiogenesis.
• Boiled the flasks of broth – then left them open
to the air and any of ‘life force’ — Life appears.
• The broth in Swan –neck flasks when left open
in air and any of ‘life force’ — no life appears
because the S- shaped curvature trapped the
microbes.
20. • In 1800s, thescientists
believed that the infectious
diseases were spread by an
entity ‘miasms’- an altered
chemical quality of
atmosphere.
• Agostino Bassi (1773 –
1856) in 1835
demonstrated that a silk
worm disease was due to a
fungal infection – the
report that a
fmirisctroorganismcould cause
disease.
Image:
https://sciencecommunication425.wordpress.com/2
21. • Edward
1796, had
vaccination
Jenner in
used
with
materials from cow
pox lesions to
protect people
against small pox.
Edward
Jenner
Image :
https://www.theschoolrun.com/
22. 1860 – 1910 : Golden age
of Microbiology
1895), Robert
– 1910) and
(1822 –
Koch(1843
others.
• Many branches of
were
Microbiology
established.
Robert Koch
• Many research works were
conducted by Louis Pasteur
Image : https://en.wikipedia.org/
23. • A series of discoveries , mostly
involving identification of
agents of diseases.
• Developed an awareness that
infectious diseases were
caused by microorganisms and
the chain of transmission could
be broken → led to
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fr,water, control
of insects,
preparation
care in the
of food for
consumption etc.
Joseph Lister
Image :
https://www.wired.com/
24. • Construction of a
bacterial filter by
Charles
Chamberland
(1884) made
possible the
discovery of
viruses and their
role in diseases.
Image :
https://en.wikipedia.org/
25. • Dmitri Iwanowski
(1892) discovered
Tobacco Mosaic
Virus (TMV) – the
first viral
pathogen
studied.
Image: https://en.wikipedia.org/
26. • Microbiology contributed
significantly to the
development of
Biochemistry – the
discovery of cell free
alcoholic fermentation by
Buchner(1897) provided
the key to chemical
analysis of energy
yielding processes. Image : https://en.wikipedia.org/
27. Contributions of Louis
PaF
sa
tt
e
hu
er
r-
of Industrial
Microbiology
• Put an end to the theory
of Abiogenesis.
• First demonstrated
that air contain
microbes.
• Discovered anaerobic life.
• E
In
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.-
chemical changes like
fermentation are vital
processes brought about
by the activity of microbes
like yeasts and bacteria.
Image
https://www.biography.com/scientist/louis-pasteur
28. • Established germ theory of disease –
microorganisms are responsible for
infectious diseases.
• Developed various methods of
sterilization- steam sterilization, hot air
oven, autoclave.
• Coined the term vaccine.
29. Contributions of F.J.
Cohn
• Discovered binary
fission – the common
method of
multiplication in
bacteria.
• Discovered
endospores
– certain bacteria form
extremely resistant
spores – Bacillus
subtilis, Clostridium
botulinum etc. Image : https://en.wikipedia.org/
30. Contributions of Robert
Koch (1843 – 1910)
Father of
Medical
• M
Firis
ct
ro
to
bir
o
e
ll
o
ag
ty
e a
specific organism to a
specific disease – the
bacterium Bacillus
anthracis causes
anthrax.
• Also discovered Bacillus
of tuberculosis
(Mycobacterium
tuberculosis ) and the
Cholera vibrio.
Image : https://en.wikipedia.org
31. KOCH’S
POSTULATES
• Robert Koch developed a series of
procedures by which a specific organism
could be related to a specific disease. These
steps are called Koch’s postulates.
i)The microorganism must be present in every
case of the disease but absent from healthy
organisms.
ii) The suspected microorganism must be
isolated and grown in a pure culture.
32. iii)The same disease must result when the
isolated microorganism is inoculated into a
healthy host.
iv)The same micro organism must be isolated
again from the diseased host.
By these procedures, a specific organism could
be related to a specific disease.
• Also developed many staining methods
for bacteria.
33. • Developed pure culture techniques
• Use of solid culture medium to grow
bacteria.
34. • In the last decade of the 19 th century,
microbiologist’s interests were concentrated on
the role of microbes as agents of infectious
diseases.
• Many of the important pathogenic organisms
have been discovered and their casual roles
established.
• The students of Pasteur, Koch and others
discovered in rapid succession a group of
bacteria capable of causing specific diseases ,
techniques and laboratory procedures.
35. • During the last decade of the
19th century, Microbiology
became an established
discipline with a distinct set of
concepts and techniques.
• During the early part of 20 th
century, Microbiology
developed independently of
other biological disciplines.
• Discovery of Electron
microscope (1934) ,
Tissue culture technique
Ernst Ruska & Max Knoll
Electron microscope
Image : https://i.pinimg.com/
36. • Development of drugs or
chemicals which could
kill infectious agents
while being non-toxic to
the host.
• In 1929 ,Sir Alexander
Fleming discovered the
antibiotic Penicillin from
Penicillium notatum,
which destroys
Staphylococci – the first
antibiotic produced from
microorganisms.
Many antibiotics are
produced from microbes. Image :
https://www.tbat.co.uk/
37. • Microbiology established a
closer relationship with other
disciplines in 1940s.
• The first important
connection between Genetics
and Microbiology is the work
of Beadle and Tatum (1941).
They succeeded in isolating
biochemical mutants in
Neurospora crassa → one
gene – one enzyme
hypothesis.
Use of microbes to produce
valuable
products→Industrial
Microbiology.
Image : https://bacterialsex.com/
38. • Development of rDNA technology
(Gene cloning or Genetic Engineering).
• Genetically modified microbes that can be
used as factory cells for the synthesis of
valuable pharmaceutical products like
human insulin, hormones, vaccines etc.
39. • Space Microbiology ( a branch of Exobiology-
investigating the possibility of
extraterrestrial life and the effects of
extraterrestrial environments on living
organisms from the earth. ) investigates the
possibility of using microbes as sources of
food and oxygen.
41. SCOPE OF
MICROBIOLOGY
Many microbiologists focus on a specific
group of microorganisms.
• Virologists – on Viruses
• Bacteriologists – on Bacteria
• Phycologists – on Algae
• Mycologists – on Fungi
• Protozoologists –on Protozoa.
43. • Public health Microbiology
• Food Microbiology
• Dairy Microbiology
• Immunology
44. Microbes - Extremely useful as
experimental materials.
• Simple
• Grow rapidly
• Can culture in large quantities in test
tubes, flasks, require less space and
maintenance than large plants and
animals.
• Easy – to – work –with material for
studying complex processes of
45. • Metabolic processes – similar to higher
plants and animals
• Microbes can be used to study synthesis of
antibiotics ,toxins, energy production,
survival mechanism in harsh
environmental conditions, microbial
nitrogen fixation etc.
