Transcript 2 History of Microbiology

History of Microbiology
1
VOCABULARY
Fermentation: the enzymatic
degeneration of carbohydrates in which
the final electron acceptor is an organic
molecule (contains carbon). For example,
ATP is synthesized by phosporylation
(adding phosphate) and oxygen is not
required. Fermentation is the process that
yeasts use to convert sugars to alcohol in
the absence of air.
 Pasteurization: the process of mild
heating to kill particular spoilage
microorganisms or pathogens.

2
VOCABULARY
Aerobic: Requires environment with
oxygen
 Anaerobic: Requires environment without
oxygen
 Facultative: Can live in environments
with and without oxygen.

3
Aristotle (384 B.C.)


Before Aristotle, people generally believed that diseases were
caused only by God. He was one of the greatest scientists of his
time. He theorized that ‘a vital force’ forms life. He noticed that
mice were commonly found in barns where grain was stored. He
thought that the mice grew from the grain and hay, and he coined
the term “Spontaneous generation”, the hypothesis that living
organisms arise from nonliving matter.
As a matter of fact, he published a recipe that anyone could use
to grow their own mice: darkness + hay + grain = mice. No one
doubted this for more than a thousand years. Eventually, a new
theory arose called the Germ Theory (disease is caused by
germs), later refined to the term “biogenesis”. Biogenesis is the
hypothesis that living organisms arise from pre-existing life. For
many years it was debated as to which of these hypotheses was
correct.
4
Aristotle
Spontaneous
Generation:
Mice grow from
straw + darkness
5
Virgil (40 A. D.)
 He
agreed with Aristotle about
spontaneous generation. He
theorized that bees grew from honey
and that flies grew from meat. Again,
this was accepted for centuries.
6
Virgil
Bees grow
from honey
and flies
grow from
meat
7
The Romans (100 A.D.)

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
During the 1st century AD (year 100), glass had
been invented and the Romans were looking
through the glass and testing it.
They experimented with different shapes of clear
glass and one of their samples was thick in the
middle and thin on the edges.
They discovered that if you held one of these
“lenses” over an object, the object would look
larger.
8
The Romans (100 A.D.)




These lenses were not used much until the end of
the 13th century when spectacle makers were
producing lenses to be worn as glasses.
The early simple “microscopes” which were really
only magnifying glasses had one power, usually
about 6X - 10X.
One thing that was very common and interesting
to look at was fleas and other tiny insects.
These early magnifiers were hence called “flea
glasses”.
9
The Romans
Used a
magnifying
lens called
“Flea glasses”
10
Zacharias Janssen (1590)




He was a Dutch spectacle maker, and started
experimenting with these lenses.
He put several lenses in a tube and made a very
important discovery.
The object near the end of the tube appeared to
be greatly enlarged, much larger than any simple
magnifying glass could achieve by itself!
He had just invented the compound microscope
(which is a microscope that uses two or more
lenses).
11
Zacharias Janssen
Invented
the first
compound
microscope
12
Janssen’s First Microscope
13
Galileo (1610)
 He
heard of their experiments and
started experimenting on his own.
 He described the principles of lenses
and light rays and improved both the
microscope and telescope.
 He added a focusing device to his
microscope and of course went on to
explore the heavens with his
telescopes.
14
Galileo
Improved the microscope,
Improved the telescope
15
Galileo’s
First
Telescope
16
Antoni Van Leeuwenhoek
(Dutch parisitologist; 1673 - 1723)




He is called the Father of Microscopy, but he did
not invent the first microscope.
He became very interested in lenses while
working with magnifying glasses in a dry goods
store.
He used the magnifying glass to count threads in
woven cloth.
He became so interested that he learned how to
make lenses.
17
Antoni Van Leeuwenhoek
(Dutch parisitologist; 1673 - 1723)




By grinding and polishing, he was able to make
small lenses with great curvatures.
These rounder lenses produced greater
magnification, and his microscopes were able to
magnify up to 270x.
He decided to look at what he thought would be
the purest substance on earth: rainwater.
He was surprised that even this pure water
contained live microorganisms (he called them
animalcules) that he also observed in teeth
scrapings.
18
Antoni Van Leeuwenhoek
(Dutch parisitologist; 1673 - 1723)





He drew pictures of what he saw and defined
names for bacteria based on their shape.
He called round bacteria cocci, rod shaped
bacteria bacilli, and spiral bacteria spirochetes.
He also described movement of bacteria by
observing Giardia lamblia in stool specimens.
He was the first person to record drawings of
microbes and he introduced the world to the
existence of microbes.
The Royal Society of London published his
drawings in their journal.
19
Antoni Van Leeuwenhoek
Improved
the simple
microscope to a
magnification of
270x
Described first
microbes.
20
Antoni Van Leeuwenhoek
21
Leeuwenhoek’s Basic Shapes
COCCI
RODS
SPIRALS
Staphylococci
Streptococci
22
Arrangements
 Pairs:
diplococci,
diplobacilli
 Clusters:
staphylococci
 Chains:
streptococci,
streptobacilli
23
Robert Hooke (1685)
 He
spent much of his life working
with microscopes and improved their
design and capabilities.
 He was the first to observe cells
while looking at tree bark.
 He reported that living things were
composed of little boxes that he
called “cells.”
24
Robert Hooke (1700’s)
Looked at cork
under a
microscope and
coined the term
“cells”
25
Robert Hooke
26
The Debate Over Spontaneous
Generation
 The
hypothesis that living organisms
arise from nonliving matter is called
spontaneous generation. According to
spontaneous generation, a “vital force’
forms life.
 The alternative hypothesis, that the
living organisms arise from preexisting
life, is called biogenesis.
27
Francisco Redi
Biogenesis
Theory:
Maggots do
not grow
from meat.
Filled covered jars
with meat
28
Francisco Redi (1668)



He doubted the theory of spontaneous generation. He
believed that maggots in meat were caused by flies laying
eggs, not by spontaneous generation as commonly
believed.
He filled six jars with decaying meat. He noted that no
maggots grew in the meat when the jars were covered. It
was argued that air was needed for the vital force to create
life. Therefore, he put a cheesecloth over half of the jars so
that flies could not come in and lay their eggs, but air could
get in.
He demonstrated that maggots grew only in the meat in
which the flasks were not covered. However, the theory of
spontaneous generation persisted because of the religious
beliefs of the time.
29
Francisco Redi
30
Evidence Pro and Con
 1668:
Francisco Redi filled six jars
with decaying meat.
Conditions
Results
3 jars covered with fine net
No maggots
3 open jars
Maggots appeared
From where did the maggots come?
What was the purpose of the sealed jars?
Spontaneous generation or biogenesis?
31
John Needham
 1780’s
 Was
an English
biologist and
Roman Catholic
priest.
 He believed in
spontaneous
generation.
32
John Needham (1749)

He was a biologist and a priest who believed in
spontaneous generation and he argued Redi’s
theory. He boiled nutrient broth to kill all
microbes, put a cork in the flask, then let it sit for
a few days. He then took a culture of the broth
and found that it contained microbes. Thus, he
“proved” that life comes only from God and a
“vital force”. He then had the scientists and the
Church on his side. He did not know that the
cork stopper was not sterilized, so microbes on it
dropped into the broth.
33
John Needham (1749)

For the next 30 years, various scientists who
disagreed with spontaneous generation tried to
disprove Needham’s experiment. One scientist
said that Needham’s cork was contaminated, so
he repeated the experiment except he sealed off
the top of the glass by melting it; no microbes
grew, so he said that spontaneous generation
was false. His opponents said that the “vital
force” that creates life is in the air, and that since
he sealed off the air, the microbes could not
spontaneously generate. Then other scientists
would repeat the experiment with their own
modifications. The debate over spontaneous
generation raged on for 30 years, dividing the
34
scientists from the religious clergy.
John Needham (1749)

In the meantime, much of the world’s commerce
was on agriculture, so there was a great concern
for keeping cattle and sheep alive. The major
diseases of this era were anthrax, the Black
Plague, smallpox, and leprosy. There were also
concerns about diseases of the money-making
crops, including grapes, tobacco, and silkworms.
While some scientists continued the debate over
spontaneous generation, others turned their
attention to the diseases at hand.
35
John Needham
Put boiled nutrient
broth into covered
flasks.
He got microbial
growth, so he said this
is evidence for
spontaneous
generation.
However, his
experiment was flawed
because the flasks and
corks were not sterile.
36
 1745:
John Needham put boiled
nutrient broth into covered flasks.
Conditions
Results
Nutrient broth heated, then placed in
sealed flask
Microbial growth
From where did the microbes come?
Spontaneous generation or biogenesis?
37
Louis Pasteur
Microorganisms
are present in
the air
38
Louis Pasteur (1880)






150 years later, Pasteur joined the spontaneous generation
debate.
He made a glass flask with an “S” shaped bend in it so that
bacteria could not enter into it.
He placed chicken broth in the flask and boiled it so that it
was sterile.
Over the next few weeks, he observed that there was no
bacterial growth in the broth, so this proved that
spontaneous generation was impossible.
No bacteria could grow unless pre-existing bacteria were
able to get in to the nutrient broth.
That ended the debate and the theory of spontaneous
generation was rejected and the theory of biogenesis was
accepted.
39
 1861:
Louis Pasteur demonstrated that
microorganisms are present in the air.
Conditions
Results
Nutrient broth placed in flask, heated,
not sealed
Microbial growth
Nutrient broth placed in flask, heated,
then sealed
No microbial growth
Spontaneous generation or biogenesis?
40
Louis Pasteur
41
The Theory of Biogenesis
 Pasteur’s
S-shaped
flask kept
microbes
out but let
air in.
42 1.3
Figure
Spontaneous Generation Theory



Aristotle thought that the mice grew
from the grain and hay, and he coined the
term “Spontaneous generation”
Virgil: bees grew from honey and that
flies grew from meat.
John Needham believed in spontaneous
generation; boiled nutrient broth to kill all
microbes, put a non-sterile cork in the
flask, found that the broth grew microbes.
43
Biogenesis Generation Theory


Redi: maggots in meat were caused by
flies laying eggs; they only grew on the
meat in which the jars were not covered.
Louis Pasteur: made a glass flask with
an “S” shaped bend in it so that bacteria
could not enter into it but air could get in.
He placed chicken broth in the flask and
boiled it so that it was sterile and
observed that there was no bacterial
growth in the broth.
44
Edward Jenner
First
vaccine:
Smallpox
45
Edward Jenner, MD (1796)
 Jenner
invented the first vaccine; it
was for smallpox, the first disease
to be eliminated from the earth by
vaccine. Some of his patients,
especially women who milked cows,
would come in with lesions filled with
pus on their hands. He went to their
farms to examine the cattle and
noticed lesions on the udders of the
cattle as well.
46
Edward Jenner, MD (1796)

Around this time smallpox was greatly feared, as one in
three of those who contracted the disease died, and those
who survived were commonly badly disfigured. Noting the
common observation that milkmaids did not generally get
smallpox, Jenner theorized that the pus in the blisters
which milkmaids received from cowpox (a disease similar to
smallpox, but much less virulent) protected the milkmaids
from smallpox. In 1796, Jenner tested his theory by
inoculating James Phipps, a young boy, with material from
the cowpox blisters of the hand of Sarah Nelmes, a
milkmaid who had caught cowpox from a cow called
Blossom. Phipps was the 17th case described in Jenner's
first paper on vaccination.
47
Edward Jenner, MD (1796)




Jenner inoculated Phipps with cowpox pus in both arms on
one day. This produced a fever and some uneasiness but no
great illness. Later, he injected Phipps with variolous
material, (weakened smallpox). No disease followed. Jenner
reported that later the boy was again challenged with
variolacious material and again showed no sign of infection.
Thus, he discovered that a genetically related microbe
could produce immunity to the smallpox pathogen.
The word vaccination comes from the Latin vaccinia,
cowpox, from vacca, cow.
In 1980, the World Health Organization declared smallpox
an eradicated disease.
48
Edward Jenner
49
Rudolf Virchow
Cell Theory
1. All living things are
composed of cells.
2. Cells are the
smallest working
units of living things.
3. All cells come from
preexisting cells by
cell division
(biogenesis theory).
50
Agostino Bassi
Silkworm disease is
caused by a fungus
51
The Golden Age of Microbiology (1880-1930)

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
Louis Pasteur (1857-1914)
Once the debate over spontaneous generation
was over, the Golden Age of Microbiology began.
Pasteur coined the terms “fermentation”,
“pasteurization, and the “Germ Theory of
Disease”.
Louis Pasteur went on to discover three
vaccines; the first was by accident.
52
The Golden Age of Microbiology (1880-1930)

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
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During his time, chicken cholera was hurting the poultry
industry. Pasteur made a pure culture of chicken cholera
and told his assistant to inoculate a chicken.
They both left on vacation and forgot to inoculate the
chicken. When they came back, they inoculated the
chicken with the same culture, which had run out of
nutrients and had become weak.
They found that the chicken never developed symptoms.
They then tested all of the chickens to make sure that
weakened culture did not cause symptoms in any chickens.
They then exposed the chickens to chicken cholera and
none of them became sick. They therefore discovered the
concept of an immune system.
53
The Golden Age of Microbiology (1880-1930)




They found that the old culture was weakened
(he called this “attenuated”), and thus he
discovered how to make the first vaccine for
chicken cholera.
Later, he found the causative agent for anthrax
and invented the sheep anthrax vaccine.
He also invented the rabies vaccine.
A vaccine is a form of artificial immunity.
54
Pasteur: Sheep Vaccine for
Anthrax
55
The Golden Age of Microbiology (1880-1930)

Louis Pasteur went on to work with anthrax,
silkworm disease, and rabies. He developed the
first vaccine for rabies, which is a disease that
spreads to the brain and spinal cord. Rabies is
caused by a virus and is too small to see under a
microscope. Therefore, he was the first to work
with human diseases caused by viruses. He
worked with rabbits that had rabies; he dissected
out the spinal cords, put them in a jar, let them
dry for a few weeks, ground them up into a
powder, and made his suspension. He then
inoculated dogs with this rabbit tissue. When the
dogs were exposed to rabies, they did not get the
disease.
56
The Golden Age of Microbiology (1880-1930)

A young boy named Joseph Meister was bitten by
a rabid animal. Back then, everyone who was
exposed to rabies died. Pasteur injected the
boy’s abdomen with a vial of the spinal cord
suspension once a week for 12 weeks. He was
the first person to survive rabies. After Louis
Pasteur died, Joseph became a caretaker of
Pasteur’s estate. During World War II the Nazis
invaded Paris. They wanted to raid Pasteur’s
tomb, but rather than allow that, Joseph
committed suicide.
57
Robert Koch
58
Robert Koch, MD (1890)

Unlike Pasteur, Koch was an MD, and he worked
with a team of scientists, rather than alone, like
Pasteur. He developed “Koch’s Postulates” which
establish the cause of disease. This was
developed using the scientific method, including
stating a hypothesis and drawing a conclusion.
He studied anthrax in sheep and cattle, and he
also discovered the cause of tuberculosis. He is
the one that proved the link between microbes
and disease. He demonstrated that a specific
microbe causes a specific disease.
59
Koch’s Postulates
Obtain the disease causing microbe from
the sick animal via a sample.
 Isolate this microbe in pure culture.
 Inoculate a healthy animal with this pure
culture, and the healthy animal should
develop the same disease.
 Re-isolate the microbe from the second
animal. If it is the same microbe obtained
from the first animal, this proves the
etiology (cause) of the disease.

60
Joseph Lister
61
Joseph Lister (1827-1912)


During his lifetime, 50% of people who had surgeries died
from post-op infections. It was thought that exposure of a
wound to oxygen caused the infection, but Lister doubted
that explanation. He was put in charge of a new hospital in
London that was designed to keep air away from post-op
wounds. However, 50% of the amputation cases still were
dying.
Then, in 1865, when Louis Pasteur suggested that decay
was caused by living organisms in the air, Lister made the
connection with wound sepsis. He considered that microbes
in the air were likely causing the putrefaction and had to be
destroyed before they entered the wound.
62
Joseph Lister (1827-1912)




In the previous year Lister had heard that carbolic acid was
being used to treat sewage in cattle fields that were
causing a parasite disease in the cattle.
Lister began to clean wounds and dress them using a
solution of carbolic acid. He reported that the surgery
patients were now recovering without infections. In 1877
he performed the first surgery using aseptic conditions,
including sterilization of instruments and hand washing
before surgeries.
Thus, he is the founder of aseptic medicine.
Later, his product was refined by another doctor who
named it Listerine® after Dr. Lister.
63
Operation using Lister's carbolic
spray invented in 1869
64
Ignaz Semmelwise
Puerperal fever could be
drastically cut by use of
hand washing standards in
obstetrical clinics.
65
Ignaz Semmelwise (1847)



Discovered that the incidence of puerperal fever
could be drastically cut by use of hand washing
standards in obstetrical clinics.
Puerperal fever (or childbed fever) was common
in mid-19th-century hospitals and often fatal,
with mortality at 10%-35%.
He also advocated that midwives should wash
their hands when going from one obstetric
patient to another to prevent transmission of
puerperal fever.
66
Paul Ehrlich
First
Antibiotic:
For syphilis
67
Paul Ehrlich (1854 –1915)



He coined the term "chemotherapy" and
developed the first antibiotic drug in modern
medicine. They called it the “magic bullet”; it was
the cure for syphylis.
After his clinical education in Berlin in 1886 he
received a call from Robert Koch to join the
Institute for Infectious Diseases in Berlin (1891).
Ehrlich spent two years in Egypt, recovering
from tuberculosis. Thereafter he worked on the
development of the diphtheria serum.
68
Paul Ehrlich (1854 –1915)




Ehrlich received the Nobel Prize for Medicine in
1908.
In 1906 he discovered the structural formula of
atoxyl, a chemical compound that had been
shown to be able to treat sleeping sickness.
Following this discovery, he tried to create a less
toxic version of the medicine. In 1909, on his
606th attempt, he developed Salvarsan, an
antibiotic effective against syphilis.
This was the first antibiotic; his work was of
epochal importance, stimulating research that led
to the development of sulfa drugs, penicillin and
other antibiotics.
69
Paul Ehrlich
70
Von Behring (1901)
Invented
diphtheria
antitoxin
First to study how a toxin
(Diptheria) can be
neutralized by an
antitoxin. He was the first
person to receive a
Nobel Prize in medicine.
71
Ross
Discovered
mosquitoes
transmit malaria
72
Metchnikoff
Discovered
White Blood
Cells and
phagocytosis:
Began field of
immunology
73
Metchnikoff (1908)



Discovered that white blood cells phagocytize
(eat) foreign particles as a fundamental part of
the immune response.
He studied mobile, amoeba-like cells (later
known as white blood cells) in starfish.
He thought they served as part of the defenses of
these organisms and, to test this idea, he stuck
the starfish with small thorns from a tangerine
tree which had been prepared as a Christmas
tree for his children.
74
Metchnikoff (1908)


Next morning he found the thorns surrounded by
the mobile cells, and, knowing that, when
inflammation occurs in animals which have a
blood vascular system, leukocytes escape from
their blood vessels, it occurred to him that these
leukocytes might take up and digest bacteria that
get into the body.
This began the field of immunology.
75
Alexander Fleming
76
Alexander Fleming
(1881-1955)




Fleming is the key person involved in the
discovery of penicillin.
One morning in the fall of 1928, Fleming noticed
a culture plate displaying a colorful green mold.
The culture plate was covered with staphylococci
except in the vicinity of the mold, which was near
the edge of the plate where there was a
transparent zone of inhibition.
The bacteria that were close to the mold had not
grown.
77
Alexander Fleming
(1881-1955)



Since his mind was prepared by his previous
studies, Fleming knew he might be on to
something that kills bacteria.
He photographed the plate and made it
permanent by exposing it to formalin vapor that
killed and fixed both the bacteria and the mold.
(The original plate is now in the British Museum.)
Fleming investigated a list of microorganisms that
were inhibited by the mold; among them were
streptococci, staphylococci, pneumococci and
meningococci.
78
Alexander Fleming
(1881-1955)



Fleming identified the mold as a Penicillium that
is similar some molds grown on bread.
In 1945 Fleming received the Nobel Prize in
Medicine and Physiology for his work with
penicillin.
NOTE: antibiotics are chemicals that kill bacteria.
It is not the same thing as an antibody, which is
a white blood cell’s natural protein that kills
bacteria.
79
The Birth of Modern
Chemotherapy
1928: Alexander
Fleming discovered
the first antibiotic.
 He observed that
Penicillium fungus
made an antibiotic,
penicillin, that killed
S. aureus.
 1940s: Penicillin was
tested clinically and
mass produced.

80 1.5
Figure
Chain and Florey
Purified penicillin as a
medicine
The biggest problem was
how to produce large
quantities of penicillin,
especially for casualties
during WWII. American
scientists Chain and
Florey were successful in
producing it for largescale manufacture.
81
Rebecca Lancefield: Invented
testing for streptococcus
82
Rebecca Lancefield
(1895 - 1981)


American microbiologist. She is most famous for
her serological classification of streptococcal
bacteria based on the antigens in the cells walls.
She also demonstrated that one of these groups,
group A streptococci (S. pyogenes), was specific
to humans and human disease, including
pharyngitis ("Strep throat"), scarlet fever,
rheumatic fever, and impetigo. Group B
streptococci were subsequently shown to be
associated with neonatal disease.
83
Lancefield’s Streptococcus
Classification
84
Frederick Griffith (1928)
Discovered
DNA
85
Watson and Crick
Detailed the
structure of
human
DNA.
86
Watson and Crick (1953)

Opened up the second golden age of
microbiology when they discovered the structure
of the DNA molecule in 1953. Watson and Crick
were awarded the 1962 Nobel Prize award, for
their body of research on nucleic acids. Their
work became the basis for the Human Genome
Project, which was a world-wide effort to list all
of the sequences of nucleic acids in human DNA.
This knowledge is helping to understand genetic
disorders. This also opened up the field of
Molecular Genetics, understanding how genes
work at a molecular level.
87
DNA Structure
Deoxyribose (sugar)
 A, T, C, G (nucleic acids)
 Phosphate (to form the
bonds)

88
Jacob and Monod (1965)
Role of
mRNA in
protein
synthesis
89
Protein Synthesis
90
Delbruck and Hershey
Structure
of viruses
91
Virus
92
Tonegawa (1987)
Antibody genetics
Genetic material
can rearrange
itself to form the
vast array of
available
antibodies.
93
Prusiner (1997)
Discovery of prions
Prions are simpler than
viruses and can cause
disease. They have no
DNA or RNA. They
cause a brain disease
called spongiform
encephalopathy (bovine
form is Mad Cow
Disease).
94
Prions
95
SELECTED NOBEL PRIZES IN
PHYSIOLOGY
1901
 1902
 1905
 1908
 1945
 1969
 1987
 1997

Behring
Ross
Koch
Metchnikoff
Fleming, Chain, Florey
Delbruck, Hershey
Tohegawa
Prusiner
diphtheria antitoxin
malaria transmission
TB bacterium
phagocytosis
penicillin
viral replication
antibody genetics
prions
96