Microorganisms and Microbiology
Chapter 1
Chapter outline
1.1 What is a microbe?
1.2 The importance of Microbiology
1.3 Microbes in our lives
1.4 The history of microbiology
1.5 Important events in the development
of microbiology
Concepts
•
Microorganisms are responsible for many of the changes
observed in organic and inorganic matter (e.g., fermentation and
the carbon, nitrogen and sulfur cycles that occurred in nature.
•
The development of microbiology as a scientific discipline has
depended on the availability of the microscope and the ability to
isolate and grow pure cultures of microorganisms.
•
Microbiology is a large discipline, which has a great impact on
other areas of biology and general human welfare
The word microbe (microorganism) is used to
describe an organism that is so small that can
not be seen without the use of a microscope.
Viruses, bacteria, fungi, protozoa and some
algae are all included in this category.
1.1 What is a microbe?
Our world is populated by
invisible creatures too small to
be seen with the unaided eye.
These life forms, the microbes
or microorganisms, may be
seen only by magnifying their
image with a microscope.
Microbial world
Organisms
(living)
Infectious agents
(non
-
living)
Prokaryotes
(unicellular)
eukaryotes
viruses
viroids
prions
Eubacteria
Archaea
Algae
(unicellular
or
multicellular)
Fungi
(unicellular
or
multicellular)
Protozoa
(unicellular)
Other
(multicellular
organisms)
Most of the bacteria, protozoa, and fungi are
single
-
celled microorganisms, and even the
multicelled microbes do not have a great range
of cell types. Viruses are not even cells, just
genetic material surrounded by a protein coat
and incapable of independent existence.
The size and cell type of microbes
Microbe
Approximate range of
sizes
Cell type
Viruses
0.01
-
0.25
µm
Acellular
Bacteria
0.1
-
10
µm
Prokaryote
Fungi
2
µm
-
>
1m
Eukaryote
Protozoa
2
-
1000
µm
Eukaryote
Algae
1
µm
-
several meters
Eukaryote
The size and cell type of microbes
Microbes impinge on all aspects of life, just a few
of these are listed below:
The environment
Medicine
Food
Biotechnology
Research
1.2 The importance of microbiology
•
The environment
•
Medicine
•
Food
•
Biotechnology
•
Research
Press here to continue
Microbes are responsible for the geochemical
cycles. They are found in association with plants
in symbiotic relationships. Some microbes are
devastating plant pathogens, but others may act
as biological control agents against diseases.
The disease
-
causing ability of some microbes
is well known. However, microorganisms have
also provided us with the means of their control
in the form of antibiotics and other medically
important drugs.
Microbes have been used to produce food,
from brewing and wine making, through
cheese production and bread making, to the
manufacture of soy sauce. But microbes are
also responsible for food spoilage.
Traditionally microbes have been used to
synthesize important chemicals. The
advent of genetic engineering techniques
has led to the cloning of polypeptides into
microbes.
Microbes have been used as model organisms for
the investigation of biochemical and genetical
processes. Millions of copies of the same single
cell can be produced very quickly and give plenty
of homogeneous experimental material. Most
people have no ethical objections to experiments
with these microorganisms.
1.3 Microbes in our lives
•
Microorganisms
as
Disease
Agents
•
Microorganisms
and
Agriculture
•
Microorganisms
and
the
Food
Industry
•
Microorganisms,
Energy,
and
the
Environment
•
Microorganisms
and
the
Future
Branches of
Microbiology
Bacteriology
Protozoology
Parasitology
Microbial Morphology
Mycology
Virology
Phycology or Algology
Microbial physiology
Microbial taxonomy
Microbial genetics
Molecular biology
Microbial ecology
The future of microbiology is bright
Microbiology is one of the most rewarding of
professions, because it gives its practitioners the
opportunity to be in contact with all the other
natural science and thus to contribute in many
different ways to the betterment of human life.
1.4 The history of microbiology
In the field of observation, chance favors
only prepared minds.
------
Louis Pasteur
The discovery of microorganisms
The spontaneous generation conflict
The recognition of microbial role in
disease
The discovery of microbial effects on
organic and inorganic matter
The development of microbiology in
this century
The discovery of microorganisms
The first person to
accurately observe and
describe microorganisms
Antony van Leeuwenhock
(1632
-
1723)
The first person to observe and describe microorganisms
was the amateur microscopist Antony van leeuwenhoek
of Delft, Holland.
Leeuwenhock made his simple, single
-
lens
microscope which could amplify the object
being viewed 50
–
300 times. Between 1673
-
1723, he wrote a series of letters to the Royal
Society of London describing the microbes he
observed from the samples of rainwater, and
humam mouth.
Leeuwenhoek’s
drawings of
bacteria from the
human mouth
.
A drawing of one
of the microscopes
showing the lens a;
mounting pin b;
and focusing
screws c and d.
lens
Object
being
viewed
adjusting
screws
Pasteur’s contributions:
Louis Pasteur working in his
laboratory
Louis Pasteur (1822
–
1895)
•
Pasteur (1857) demonstrated
that lactic acid fermentation is
due to the activity of micro
-
organisms
•
Pasteur (1861) conflict over
spontaneous generation
–
birth
of microbiology as a science
•
Pasteur (1881) developed
anthrax vaccine
•
Pasteurization
Spontaneous generation
–
that living
organisms could develop from nonliving
or decomposing matter.
The spontaneous generation conflict
Pasteur’s swan neck flasks used in his experiments
on the spontaneous generation of microorganisms
Conclusion:
Microorganisms are not spontaneously
generated from inanimate matter, but
are produced by other microorganisms
Robert Koch in his laboratory
The recognition of microbial role in disease
Robert Koch (1843
–
1910)
Koch’s demonstration of special organisms
cause special diseases
Koch’s postulates
•
The microorganisms must be present in every
case of the disease but absent from healthy
organisms.
•
The suspected microorganisms must be isolated
and grown in a pure culture.
•
The disease must result when the isolated
microorganisms is inoculated into a healthy
host.
•
The same microorganisms must be isolated
again from the diseased host
The Golden age of microbiology
•
Koch and pure cultures
•
Fermentation and Pasteurization
•
Germ theory of disease
•
Vaccination
The discovery of microbial
effects on organic and
inorganic matter
•
The Russian microbiologist
Winograsky discovered that soil
bacteria could oxidize iron, sulfur
and ammonia to obtain energy,
and also isolated nitrogen
–
fixing
bacteria.
•
Beijerinck made fundamental
contributions to microbial ecology.
He isolated Azotobacter and
Rhizobium.
Alexander Fleming
(1881
-
1955
)
Sir Alexander Fleming
discovered the antibiotic
penicillin. He had the
insight to recognize the
significance of the
inhibition of bacterial
growth in the vicinity of
a fungal contaminant.
Date Microbiological History
1676 Leeuwenhoek discovers "animalcules"
1857
Pasteur shows that lactic acid fermentation is due to a
microorganism
1861
Pasteur shows that microorganisms do not arise by
spontaneous generation
1867 Lister publishes his work on antiseptic surgery
1869 Miescher discovers nucleic acids
1876
-
1877 Koch demonstrates that anthrax is caused by Bacillus
anthracis
1880
Laveran discovers Plasmodium, the cause of malaria
1881 Koch cultures bacteria on gelatin
Pasteur develops anthrax vaccine
1.5 Important events in the development
of microbiology
1884 Koch's postulates first published Metchnikoff describes
phagocytosis Gram stain developed
1887 Petri dish (plate) developed by Richard Petri
1889
Beijerinck isolates root nodule bacteria
1899
Beijerinck proves that a virus particle causes the tobacco
mosaic disease
1921 Fleming discovers lysozyme
1923 First edition of Bergey's Manual
1928 Griffith discovers bacterial transformation
1929 Fleming discovers penicillin
1933
Ruska develops first transmission electron microscope
1935 Stanley crystallizes the tobacco mosaic virus
1944
Avery shows that DNA carries information during
transformation Waksman discovers streptomycin
Watson and Crick propose the double helix structure
for DNA
1961
-
1966 Cohen et al use plasmid vectors to clone genes in
bacteria
1980 Development of the scanning tunneling microscope
1983
-
1984 The polymerase chain reaction developed by Mullis
1990 First human gene
-
therapy testing begun
1997
Discovery of Thiomargarita namibiensis, the largest
known bacterium Escherichia coli genome sequenced
2000
Discovery that Vibrio cholerae has two separate
chromosomes
1
.
How
did
Pasteur's
famous
experiment
defeat
the
theory
of
spontaneous
generation?
2
.
How
can
Koch's
postulates
prove
cause
and
effect
in
a
disease?
3
.
Who
was
the
first
person
to
use
solid
culture
media
in
microbiology?
What
advantages
do
solid
media
offer
for
the
culture
of
microorganisms?
REVIEW QUESTIONS:
4
.
What
is
the
enrichment
culture
technique
and
why
was
it
a
useful
new
method
in
microbiology?
5
.
When
and
how
Alexander
Fleming
discovered
antibiotics?
1
.
Pasteur's
experiments
on
spontaneous
generation
were
of
enormous
importance
for
the
advance
of
microbiology,
having
an
impact
on
the
methodology
of
microbiology,
ideas
on
(he
origin
of
life,
and
the
preservation
of
food,to
name
just
a
few
.
Explain
briefly
how
the
impact
of
his
experiments
was
felt
on
each
of
the
topics
listed
.
APPLICATION QUESTIONS:
2. Describe the various lines of proof
Robert Koch used to definitively associate
the bacterium Mycobacterium tuberculosis
with the disease tuberculosis. How would
his proof have been flawed if any of the
tools he developed for studying bacterial
diseases had not been available for his
study of tuberculosis?
Ronald M.Atlas Clifford Renk Principles of Microbiology.
沈萍
†
1999⸠
微生物学
高等教育出版社。
J
。尼克林著
林雅兰等译。
科学出版社。
周德庆
†
2002⸠
微生物学教程
†
第二版。高等教育出版社。
李阜棣
†
胡正嘉
⸠2000
微生物学。
第五版。中国农业出版社
。
赵斌
†
何绍江
⸠′ 02
微生物学实验。科学出版社。
Johnson.case. Laboratory Experiments in Microbiology.
John P.Harley Lansing M.Prescott Microbiology 3th Edition.
Lansing, M. Prescott ;John, P. Harley; and Donald, A. Klein . 2002. Microbiology, 5th ed. McGraw
-
Hill .
Gerard J. Tortora ; Bardell R. Funke ; Christine L. 1998. Case. Microbiology An Introduction , 6th .
Benjamin/Cummings.
Michael, T. Madigan; John, M. Martinko; and Jack, Parker. 2003. Brock Biology of Microorganisms ,
10th . Prentice
-
Hall.
References:
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