Video Conferencing 1: 19th September 2015
JIB 221 MICROBIOLOGY
Chapter 1
The Main Themes of Microbiology
Outline
Historical of microbiology
Diversity of microbes
Evolutionary time line of microbes
Taxonomy of organism/microbes
Energy & nutrient flow of microbes
Used of microorganisms
Infectious diseases
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Definition
Microbiology: specialized biology for
the study of microorganism
Microorganisms (microbes)
- Microscopic: require magnification to
be seen/observed/studied
- Include: bacteria; viruses; fungi;
protozoa; helminthes; algae
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Fields & Occupations
Immunology:
Study the complex web of protective
substances and reactions caused by
the invading microbes and other
harmful entities.
Public Health Microbiology
& Epidemiology
Public Health Microbiology
& Epidemiology:
Monitor & control the spread of disease in
communities. Genetic Engineering
& Recombinant DNA Technology
Fields & Occupations
Biotechnology:
Any process that harnesses the
actions of living things to arrive at a
desired product. E.g. industrial
microbiology for the production of
e.g. vaccines, drugs, enzymes.
Public Health Microbiology
& Epidemiology
Genetic Engineering
& Recombinant DNA
Technology:
Deliberate alterations of the genetic
makeup of organisms to create novel Genetic Engineering
Recombinant DNA Technology
microbes, plants & animals with& unique
behavior and physiology.
Origins of Microorganism
Bacteria-like organism
~3,500,000,000-year-old
Human
(Homo sapiens)
~195,000-year-old
Structure of Microbes
Microbes Structure
Prokaryote
Unicellular
Eukaryote
Unicellular /
Multicellular
Virus
Acellular
No nucleus With nucleus No nucleus
No
organelles
With
organelles
With nucleic
acid &
protein
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Microbes: Diversity
Bacteria: Mycobacterium tuberculosis, a
rod-shaped cell (15,500x).
Virus: Herpes simplex, cause of cold
sores (100,000x).
Fungi: Thamnidium, a filamentous
fungus (400x)
Protozoa: A pair of Vorticella (500x), stalked cells
that feed by means of a whirling row of cilia.
Algae: desmids, Spirogyra filament, and diatoms
(golden cells) (500x).
Helminths: Cysts of the parasitic roundworm,
Trichinella spiralis (250x) embedded in muscle.
Microbes: Dimension
Log10 of meters
Metric Scale
1,000 kilometer (km)
100 hektometer (hm)
10
dekameter (dam)
1.
meter (m)
-1
0.
decimeter (dm)
-2
0.
centimeter (cm)
-3
0.
millimeter (mm)
-4
0.
-5
0.
-6
0.
-7
0.
-8
0.
-9
0.
nanometer (nm)
-10
0.
Angstrom ( )
-11
0.
-12
0.
micrometer (mm)
picometer (pm)
Microbes: Dimension
~10 nm (Poliovirus)
~4 mm (protozoa)
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Energy & Nutrient Flow
Photosynthesis
Decomposition
Release O2
Back to natural cycles
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Energy & Nutrient Flow
Earth ecosystem:
- Photosynthesis: light fueled
conversion of CO2 to organic material
- Decomposition: breakdown dead
matter and wastes into simple
compounds; directed back to natural
cycles
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Human Usage of Microbes
Biotechnology
Bioremediation
Algae Biofuel
Shewanella:
water treatment
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Human Usage of Microbes
Biotechnology: produce food, drugs,
vaccines using living organism
Genetic engineering: manipulate
genes of microbes to make new
products
Bioremediation: microbes to remedy
environmental problem
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Lifestyles of Microbes
Majority
: free existence
: relatively harmless
: often beneficial
Some : have close associations with
other organisms
Parasite : live on or in the body of
other organism (host)
: damages the host
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Infectious Diseases
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Infectious Diseases
Total
Infectious Diseases (35%)
32.20 million
11.30 million
Infectious Diseases
Pathogens: parasite microbes that
lives in the body of host and derives its
requirement from the host
> 2000 pathogens caused various
diseases in human
Worldwide:
~10 billion new infections/year
~12 million deaths from infections/year
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Historical Foundations of
Microbiology
Prominent discoveries:
- Microscope
- Scientific method
- Medical microbiology
- Microbiology techniques
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Spontaneous Generation
Early belief that some forms of life
could arise from vital forces present in
non-living or decomposing matter (e.g.
flies from manure, etc)
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Louis Pasteur
Disproved: spontaneous generation
Proved: Theory of Biogenesis
: Living things can only arise
from other living things
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Historical of Microbiology
Antonie van Leeuwenhoek (1623-1723)
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Antonie van Leeuwenhoek
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Antonie van Leeuwenhoek
1st to observe living microbes
Built microscopes: magnify > 300X
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Scientific Method
A proper approach taken by scientists
to explain certain natural phenomenon
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Scientific Method
Hypothesis
(If .., then ..)
Experiment, analysis & testing
(support or refute the hypothesis)
Published results (repeatable)
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Scientific Method
Investigation of bacterial endospores
Hypothesis
Predictions
Bacterial
endospores
are the most
resistant
of all cells on earth.
If hypothesis is true,
endospores can survive
extreme conditions
such as:
Testing
Theory/Principle
Compare endospore formers to non-endospore
microbes.
Survival of
endospore former
Survival of
non-endospore former
temperature (boiling).............................+................................../+*
radiation (ultraviolet).............................+...................................
Endospores are the only
cells consistently capable of
surviving a wide range of
destructive environmental
conditions. In order to
sterilize, these cells must be
eliminated.
lack of water (drying)............................+.................................../+
chemicals.............................................+.................................../+
(disinfectants)
*Only 1 out of 4 cell types survives.
Endospores
of certain
bacteria
Cells without
endospores are
ordinary
bacteria,
fungi, animal
cells.
Endospores
Additional tests show that endospores
have thick coverings and protective features
and that endospores are known to survive
over millions of years.
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Scientific Method
If the hypothesis is supported by a
growing body of evidence & survives
rigorous scrutiny
Theory
If the evidence of a theory is so
compelling that the next level of
confidence is reached
Law / Principle
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Aseptic Techniques Development
Human body is a source of infection
Dr. Oliver Wendell Holmes- observed
mothers of homebirths had fewer
infections than those who gave birth in
hospitals
Dr. Ignaz Semmelweis- correlated
infections with physicians coming
directly from the autopsy room to the
maternity ward
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Aseptic Techniques Development
Joseph Lister
- Introduced aseptic techniques to
reduce microbes in medical setting
& prevent wound infections
- Disinfection of hands using
chemicals prior to surgery
- Use of heat for sterilization
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The Germ Theory of Disease
Many disease are caused by the
growth of microbes in the body
Disease are not caused by sins, bad
character, poverty etc
Contributed by Louis Pasteur & Robert
Koch
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Historical of Microbiology
Louis Pasteur (1822-1895)
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Louis Pasteur
Showed microbes caused fermentation
& spoilage
Disproved spontaneous generation of
microbes
Developed pasteurization
Demonstrated Germ Theory of
Disease
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Historical of Microbiology
Robert Koch (1843-1910)
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Robert Koch
Established Kochs postulates:
sequence of experiments to verified
Germ Theory of Disease
Identified caused of anthrax,
tuberculosis & cholera
Developed pure culture methods
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Taxonomy
Organizing, classifying &naming living
things
Classification: orderly arrangement of
organisms into groups
Nomenclature: assigning names
Identification: determining & recording
the traits of organisms for taxonomic
placement
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Level of Classification
Domain: Acheaea, Bacteria & Eukarya
Kingdom
Phylum / Division
Class
Order
Family
Genus
Species
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Sample Taxonomy
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Assigning Specific Names
Binomial system of nomenclature
Giving each organism 2 names:
- Genus: capitalized first letter
- Species: lowercase
Italic or underlined; e.g.
Staphylococcus aureus
(Staphylococcus aureus)
S. aureus (S. aureus)
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Origin & Evolution of Microbes
Phylogeny- natural relatedness
between groups of organisms
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Origin & Evolution of Microbes
Evolution- All new species originate from
preexisting species
- Closely related organism have
similar features because they
evolved from common ancestral
forms
- Usually progresses toward greater
complexity
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Traditional Whittaker System
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Traditional Whittaker System
Based on cell structure & type, the
nature of body organization, and
nutritional type
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Woese-Fox System
Kingdoms
Plantae
Domain Bacteria
Cyanobacteria
Chlamydias
Spirochetes
Domain Archaea
Gram-positive Endospore
bacteria
producers
Gram-negative
bacteria
Methane
producers
Ancestral Cell Line (first living cells)
Prokaryotes
that live in
extreme salt
Animalia
Fungi
Domain Eukarya
Prokaryotes
that live in
extreme heat
Eukaryotes
Protista
Woese-Fox System
Based on the origins of cell lines
3 domains of life:
- Bacteria: true bacteria
- Archaea: odd bacteria that live in
extreme environment e.g. high salt,
heat
- Eukarya: have a nucleus &
organelles
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Woese-Fox System
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