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Introduction to Microbiology
• What is Microbiology?
- Micro - too small to be seen with the naked eye
- Bio - life
- ology - study of
• Microbiology can be defined as: It is science dealing with the
study of small microorganism.
• Organisms included in the study of Microbiology:
1. Bacteria
Bacteriology
• 2. Protozoans
Protozoology
• 3. Algae
Phycology
• 4. Parasites
Parasitology
• 5. Yeasts and Molds
Mycology
• Fungi
• 6. Viruses
Virology
Bacteriology:
• It is science to deal with the study of the bacteria.
Virology:
• It is science to deal with the study of the virus.
Mycology:
• It is science to deal with the study of fungi.
Immunology:
• It is the science to deal with the resistance of the body to
any foreign substance.
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Parasitology:
• It is the science to deal with Parasites.
The importance of microorganisms:
• Microorganisms are the oldest forms of life.
• Microorganisms have the greatest biomass.
• Microorganisms have killed more people than have ever been
killed in wars.
• Without certain microorganism life could not exist; produce O2 and
N2 .
• Microorganisms are decomposers.
BRANCHES OF STUDY WITHIN MICROBIOLOGY
• Immunology
• Public health microbiology & epidemiology
• Food, dairy and aquatic microbiology
• Biotechnology
• Genetic engineering & recombinant DNA technology
MICROBES ARE INVOLVED IN
• Nutrient production & energy flow
• Decomposition (bioremediation)
• Production of foods
• Production of drugs & vaccines
• Genetic engineering
• Causing disease
History of the Study of Microorganisms:
- 1665 Robert Hooke
• “little boxes” - “cells”
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• Cell Theory - all living things are made up of cells
• Anton van Leeuwenhoek 1674 who was the first person to
actually see living microorganisms
• 1590 – First compound light microscope
Janssen
Zacharias
•
Anton Von Leeuwenhoek 1676 –first observation of bacteria
“animalcules
• *As a tailor, used lenses to examine cloth. It was probably this that
led to his interest in lens making.
• *He assembled nearly 250 microscopes, some of which magnified
objects 270 times.
• *As he looked at things with his microscopes, he discovered
presence of “micro” organisms - organisms so tiny that they were
invisible to the naked eye.
• *He called these tiny living organisms “animalcules”. He first
described bacteria and the protozoans.
•
Edward Jenne
1796 – First vaccine (smallpox)
• Rudolph Virchow 1858 the owner of the Theory of
Biogenesis, that said ; Cells can only arise from preexisting
cells
• 1857 – Germ Theory of Disease
Louis Pasteur
• 1884 Disease transmission Robart koch Koch’s Postulates
who established the relationship between Bacillus anthracis and
anthrax; also isolated the bacillus that causes tuberculosis
• 1885 - Vaccine against Rabies
Louis pasteur
- Developed vaccines for Chickenpox, anthrax, rabies
_Demonstrated that all fermentations were due to the activities of
specific yeasts and bacteria.
•
Alexander Fleming
antibiotic)
1929
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Discovery of Penicillin (first
- British bacteriologist observed bacterial staphylococci colonies
disappearing on plates contaminated with mold.
- Fleming extracted the compound from the mold responsible for
destruction of the bacterial colonies.
- The product of the mold was named penicillin, after the
Penicillium mold from which it was derived
• 1938 – First Electron Microscope
The electron microscope is capable of magnifying biological
specimens up to one million times. These computer enhanced
images of 1. smallpox, 2. herpes simplex, and 3. mumps are
magnified, respectively, 150,000, 150,000 and 90,000 times.
• Watson & Crick
• Jonas Salk
1953 Structure of DNA Revealed
1954 Polio Vaccine
Golden Age of Microbiology 1857 - 1914 Recent History
Pasteur
• Pasteurization
• Fermentation
Joseph Lister
• Phenol to treat surgical wounds – 1st attempt to control
infections caused by microoganisms
Robert Koch
• Koch’s Postulates
Edward Jenner
• vaccination
Paul Erlich
• 1st synthetic drug used to treat infections
• Salvarsan - arsenic based chemical to treat Syphilis
Recent history:
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• Genetic engineering
• Cloning
• Human Genome Project
• Biotechnology
• Who knows what is next?
Sizes of Microbes
• Virus -
10 →1000 nanometers *
• Bacteria - 0.1 → 5 micrometers **
(Human eye ) can see .1 mm (1 x 10 -3 m)
* One billionth or 1 x 10 -9 m
** One millionth or 1 x 10 -6 m
Tools of Microbiology
1. Compound light Microscope
- live specimens
- 1,000 mag. or less
2. Electron Microscope
- non-living specimens
- > 1,000 X mag.
3. Incubator – keep microbes warm for growth
Techniques of Microbiology
- Staining – to better see structures
- Microbial Culture - growing the tiny beasties
• Container for microbe culture - usually Petri dish
• Culture media
• Food for the microbes
- E.g. Agar – (from red algae)
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- Others such as nutrient broths
Pure Culture Techniques
1. Inculcation
2. Isolation
3. Identification
Biological Hierarchical Classification
When classification schemes were first developed, all living organisms
could easily be placed in a general category, like Kingdom Plantae or
Kingdom Animalia. General categories, such as Kingdoms still work
well in classification but they break down when some organisms in one
category have characteristics which are similar to organisms in another
category . A case in point is the one-celled organism, Euglena, which
bears both animal and plant
• Taxonomic categories
Depend on this classification; the Living Organisms is divided in to 3
Domains
1978 Carl Woese
• 1. Bacteria
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• Unicellular prokaryotes with cell wall containing
peptidoglycan
• 2. Archaea
• Unicellular prokaryotes with no peptodoglycan in cell
wall
• 3. Eukarya
• Protista
• Fungi
• Plantae
• Animalia
Depend on this classification, we can divide the Living Organisms
in to 6 Kingdoms :
1. Animalia
2. Plantae
3. Fungi
4. Protista
5. Arcaebacteria
6. Eubacteria
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Type of cells
1. Prokariotic cells: bacteria and blue-green algae
2. Eukariotic cells: fungi and protozoa
3. Viruses: infective particle that need a viable cell for their
replication and can be seen using EM
Procaryotes: relative simple morphology and lack true membrane
defined nucleus
Eucaryotes: morphologically complex with a true membrane enclosed
nucleus
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viruses
- Since viruses are acellular and possess both living and nonliving
characteristics, they are considered neither prokaryotic nor eukaryotic.
They will be discussed in separate section of the course
Domain: Archaea
• Prokaryotic
• Lack peptidoglycan
• Often live in extreme environments
• Not known to cause disease in humans or animals
• Had been considered bacteria until examination of their unique
rRNA sequences.
- Includes:
– Methanogens
– Extreme halophiles
– Extreme thermophiles
• Scope of Microbiology:
• Microbiology has an impact on medicine, agriculture, food science,
ecology, genetics, biochemistry, immunology, and many other
fields.
Many microbiologists are primarily interested in the biology of
microorganisms, while others focus on specific groups;
Virologists - viruses
Bacteriologists - bacteria
Phycologists – algae
Mycologist -fungi
Protozoologists – protozoa
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Medical Microbiology: deals with diseases of humans and animals;
identify and plan measures to eliminate agents causing infectious
diseases.
Agricultural Microbiology: impact of microorganisms on agriculture;
combat plant diseases that attack important food crops.
Food and Dairy Microbiology: prevent microbial spoilage of food &
transmission of food-borne diseases (e.g. salmonellosis); use
microorganisms to make food such as cheeses, yogurts, pickles, beer, etc.
Industrial Microbiology: using microorganisms to make products such
as antibiotics, vaccines, steroids, alcohols & other solvents, vitamins,
amino acids, enzymes, etc.
Genetic Engineering: Engineered microorganisms used to make
hormones, antibiotics, vaccines and other products.
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