Chapter 1 Outline:
Introduction and History of Microbiology
Define:
Microbiology
– the study of little life forms
Microbe, microorganism, agent
-- microbe = microorganisms and nonliving agents
-- microorganism = small organism
-- agent – nonliving entity studied in microbiology
Germ, pathogen
-- disease-causing microbe
List several ways in which microbes affect
us:
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Photosynthesis
Nitrogen fixing
Break down wastes/organic matter
Part of normal flora on/in our bodies
Used to produce food: yogurt, bread, wine, etc.
Make vaccines, insulin, enzymes
Bioremediation: cleaning up pollution, ex. Oil spills
Pathogens
Photosynthetic cyanobacteria
Nitrogen fixing
N2  amino acids (used to build proteins)
Break down wastes/organic matter
Normal flora (microbiota)
Foods produced by microbes
Making products
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Bacterial chromosome
Example:
+
Human insulin gene
E. coli
Human insulin
Human insulin gene
inserted into
chromosome
Bioremediation
Alaska-in-pictures.com
http://www.alaska-in-pictures.com/bioremediation-project-3253-pictures.htm
Naming and classifying microbes
Naming
Organisms
Scientific names
2 parts
genus + specific epithet = species name
underlined or in italics
genus capitalized; specific epithet not
Non-living (like viruses and prions)
Usually named for disease, condition
Classifying
Organisms
3 Domains:
Eubacteria (true bacteria, includes pathogens)
Archaea (archaebacteria, live in extreme env.)
Eukarya (plants, animals, fungi, protistans)
Prokaryotes vs. eukaryotes
Non-living (viruses)
Based on characteristics, such as DNA vs. RNA
Virus classification
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Type of nucleic acid
Ds (double-stranded) or ss (single-stranded)
Enveloped vs. non-enveloped
Shape
Types of microbes studied in microbiology:
1. bacteria:
prokaryotic
unicellular
peptidoglycan cell wall
divide by binary fission
Figure 1.1a
2. viruses:
acellular
nucleic acid + protein coat (capsid)
parasitic in host cells
3. fungi:
eukaryotic
secrete digestive enzymes and absorb nutrients
molds, yeasts, etc.
Figure 1.1b
4. protists (sometimes called protozoans):
eukaryotic
unicellular
classified by means of movement, ex. Amoeba
Figure 1.1d
Giardia movie clip
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1_13_giardia.mov.zip
5. helminths:
multicellular worms – usually diagnosed by microscopy
ex. Tapeworms, pinworms
6. prions:
infectious proteins
newly discovered
Ex. Mad Cow disease, Creutzfeldt-Jakob disease, scrapie,
kuru
Normal protein and prion
7. the immune system:
body’s response to pathogen
action of pathogen
humoral vs. cellular immunity
(antibodies)
(T cells—virally infected cells, cancer)
Figure 1.1e
Antibodies attaching to bacterium
T cells
Branches of microbiology:
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Bacteriology
Virology
Mycology
Parasitology
Molecular biology
Immunology
History of microbiology
Ancient times
Production/preservation of foods
Embalming
1600s to 1800
Robert Hooke and his “cells” of cork
Antony van Leeuwenhoek sees first living “animalcules”
Francesco Redi and his jars of meat (starts to disprove
spontaneous generation)
Edward Jenner and the first vaccine (against smallpox)
Figure 1.2 - Overview
courtesy of CDC/ Jean Roy
Public Health Image Library
History of microbiology
1800s
Louis Pasteur disproves spontaneous generation with
swan neck flasks
His other work:
Fermentation processes caused by microbes
Wine industry and pasteurization (control of
microbes)
Silkworm disease caused by protozoan
Rabies vaccine and Joseph Meister
Isolation of viruses by filtration through
porcelain
Figure 1.3 - Overview
Bacillus anthracis
Courtesy of CDC/ Dr. William A. Clark
Public Health Image Library
A case of cutaneous anthrax
Courtesy of CDC
Public Health Image Library
History of microbiology
The Germ Theory
Robert Koch (“coke”) and Bacillus anthracis
diseases had been associated with bad/immoral behavior,
punishment from God, evil spells, swamp vapors, etc. …
not microbes…until Koch
Koch’s Postulates:
1. Disease and microbe must always be present together
in host.
2. Isolate microbe in pure culture.
3. Infect new, healthy host with microbe from pure
culture and produce disease again.
4. Reisolate microbe from 2nd host in pure culture.
(Development of agar and establishment of pure cultures were crucial to Koch’s Postulates.)
Robert Koch
1843-1910
History of microbiology
Joseph Lister: surgeon who first sterilized surgical
instruments and wounds
Ignaz Semmelweis: hand hygiene prevents childbed fever
Maternal Mortality due to Postpartum Infection
General Hospital, Vienna, Austria, 1841-1850
Semmelweis’ Hand
Hygiene Intervention
Maternal Mortality (%)
18
16
14
12
10
8
Hand Hygiene: Not a New
Concept
6
4
2
0
1841
1842
1843
1844
1845
MDs
1946
1847
1848
1849
1850
Midwives
~ Hand antisepsis reduces the frequency of patient infections ~
Adapted from: Hosp Epidemiol Infect Control, 2nd Edition, 1999.
History of microbiology
1900s:
Paul Ehrlich and salvarsan: first chemical treatment for disease (syphilis)
Sulfa drugs
Alexander Fleming and penicillin
1940s and WWII – mass production of penicillin
1950s – Age of Antibiotics begins
1953 – structure of DNA
1970s – restriction enzymes (molecular “scissors”) discovered
1980s – PCR = polymerase chain reaction; copying DNA
1997 – prions
2000 – the Human Genome Project
2001 – 9/11/2001 and bioterrorism
2003 – new disease called SARS; first case of the “bird”flu
2005 – growing awareness of the avian flu; world governments mobilize/prepare
2009 – H1N1 influenza (swine flu)
Alexander Fleming
Figure 1.5
Kary B. Mullis
The Nobel Prize in Chemistry 1993
the polymerase chain reaction (PCR) method
Dr Bruce Ivins, a a biodefense researcher at
Fort Detrick. Photograph: Frederick News
Post/AP
“Detrick anthrax scientist commits suicide as FBI closes in”
August 01, 2008
The End