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MICROBIOLOGY 2011 PROFESSOR M.
“It is, in fact, nothing short of a miracle that
the modern methods of instruction have not
entirely strangled the holy curiosity of
inquiry.”
Albert Einstein
A Light Microscope - the models found in most schools, use
- compound lenses and light to magnify objects. The lenses
bend or refract the sunlight or lights in a room, which makes
the object beneath them appear closer. 1000 x magnification
Stereoscope - this microscope allows for binocular (two eyes)
viewing of larger specimens. 40-70 magnification
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ELECTRON
Developed in
1930’s
Expensive
Large structure
Views electrons
Images are B/W
Higher resolution
High radiation
exposure
2 million
magnification
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LIGHT
Developed 1590
Less expensive
Smaller structure
Views photons
Images in color
Lower resolution
No radiation
exposure
Magnifies 1-2,000
x
Scanning Electron Microscope - allow scientists to view a universe too
small to be seen with a light microscope. SEMs don’t use light waves; they
use electrons (negatively charged electrical particles) to magnify objects up
to two million times. Three dimensional view.
Transmission Electron Microscope - also uses electrons, but instead of
scanning the surface (as with SEM's) electrons are passed through very thin
specimens. Two dimensional view.
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SEM
http://www.ualberta.ca/~mingchen/images.htm
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SEM
http://www.ualberta.ca/~mingchen/images.htm
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TEM
http://www.ualberta.ca/~mingchen/images.htm
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TEM
http://www.ualberta.ca/~mingchen/images.htm
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14th century – Italy – lens ground; used for
improving vision
1590 – Janssen brothers made 1st scope by
placing two lenses in a tube.
1667 – Robert Hooke studies various objects
with his microscope and publishes his results
in Micrographia.
1675 – Anton van Leeuwenhoek uses a simple microscope with
only one lens to look at blood, insects and many other objects. He
was first to describe cells and bacteria, seen through his very small
microscopes with, for his time, extremely good lenses.
18th century – Several technical innovations make microscopes
better and easier to handle, which leads to the use of microscopes
becoming more and more popular among scientists. An important
discovery is that lenses combining two types of glass could reduce
the chromatic effect, with its disturbing halos resulting from
differences in refraction of light.
1830 –Lister’s refinement reduces the problem with spherical
aberration by showing that several weak lenses used together at
certain distances gave good magnification without blurring the
image.
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Van Leeuwenhoek (1632 – 1723) 1st to see
bacteria = Father of Microbiology;
magnification of his lenses - 200-300x
Pasteur (1822- 1895) – fermentation; coined
terms aerobe and anaerobe; heated fluids to
kill bacteria that caused his wine to go bad =
Pasteurization (only kills pathogens); made
vaccines for animals
What is up with the fad in Pa. for ‘raw’ cow’s
milk?
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The bacteria must be present in every case of
the disease.
The bacteria must be isolated from the host
with the disease and grown in pure culture.
The specific disease must be reproduced
when a pure culture of the bacteria is
inoculated into a healthy susceptible host.
The bacteria must be recoverable from the
experimentally infected host
1938 – Ernst Ruska develops the electron microscope.
The ability to use electrons in microscopy greatly improves the
resolution and greatly expands the borders of exploration.
The Nobel Prize in Physics 1986 »
1981 – Gerd Binnig and Heinrich Rohrer invent the scanning tunneling
microscope that gives three-dimensional images of objects down to the
atomic level.
The Nobel Prize in Physics 1986 »
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1. Etiology – cause or theory of origin
2. Incidence – range of occurrence; tendency
to affect groups differently
3. Morbidity – % affected people/ population
in a given time frame
4. Mortality - % deaths from given disease
within given time frame
5. Idiopathic – no known cause
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6. Iatrogenic – caused by adverse effects of tx
7. Communicable disease - transmittable
8. Endemic – a few people always have a
given illness in a certain area (common cold)
9. Epidemic – many people in a given area are
sick with same disease at same time (flu)
10. Pandemic – a disease seen throughout an
entire country, continent or the world (HIV)
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Primitive organism
Binary fission for cell
division
No membrane bound
organelles/ nucleus
Has separating
membrane and cell
wall
Ex: Bacteria and bluegreen algae
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Evolved; advanced
True nucleus with a
membrane
Cell division - mitosis
Animal – meiosis
Fungi, protozoa,
green/red/brown
algae, plant and animal
cells
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Indigenous flora – microbes found growing
on/ within our body every day
Pathogen – a disease causing microorganism
Host – The organism on/in which the parasite
lives (its source of nutrition)
Parasite – a microorganism relies on host for
its needs to the detriment of the host
Opportunistic infection – an organism that is
able to cause a disease because the host’s
health has been compromised
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When a microorganism is growing but does
not cause inflammatory changes in the
location of the growth.
EX: Bacteria present in nasal passages. Nasal
passages are free from signs and symptoms
of bacterial presence. No redness, swelling,
pain or heat in the area.
The bacteria is still transmittable.
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Direct contact
Indirect contact – fomite
Droplet
Airborne
Vehicle – bad food, water
Vector – flea, mosquito, tick, rats
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Kingdom
Phyllum
Class
Order
Family
Genus*
Species*
◦ Species members share a basic genetic similarity
and can interbreed and produce viable or fertile
offspring.
http://en.wikipedia.org/wiki/Clostridium
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Clostridium difficile
Clostridium botulinum
Clostridium sodellii
Clostridium tetani
Clostridium perfringens
These 5 are the most commonly seen but
there are many others in this species…….
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C. Acetobutylicum, C. argentinense
C. aerotolerans
C. baratii, C. beijerinckii, C. bifermentans, C. botulinum, C. butyricum
C. cadaveris, C. cellulolyticum, C. chauvoei, C. clostridioforme
C. colicanis, C. difficile, C. estertheticum, C. fallax, C. feseri
C. formicaceticum, C. histolyticum, C. innocuum, C. kluyveri
C. ljungdahlii, C. laramie, C. lavalense, C. nigrificans, C. novyi
C. oedematiens, C. paraputrificum, C. perfringens, C. phytofermentans
C. piliforme, C. ragsdalei, C. ramosum, C. scatologenes, C. septicum
C. sordellii, C. sporogenes, C. sticklandii, C. tertium, C. tetani,
C. thermocellum, C. thermosaccharolyticum, C. tyrobutyricum
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Definition: shape
Bacilli
Cocci
Vibrios
Spirallae
Spirochete
Check your handout
Cocci, round bacteria
(Gram stained).
• What word
describes the shape
and arrangement of
the cells in D?
Bacilli, rod-shaped bacteria.
Curved rods
• What feature indicates that the cells in A
are capable of movement?
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Single cell
Paired cells
Chains of cells
Clusters of cells
Color
Size
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Bacteria
Fungal
◦ Yeasts – single cell
Molds - filamentous
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Rickettsiae
Viral
Protozoal
Metazoal (helminths)
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Metabolism
◦ Physical & chemical processes involved in
maintaining life
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Growth
Ability to reproduce
Irritability (able to react to environment)
Motion – gliding, flagella, axial filaments
Protection
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Light
◦ Amount
◦ Type
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Temperature
Moisture
Food Availability
Oxygen supply
pH
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Spore
Capsules
Flagella
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Drug resistance
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Endotoxins
◦ Poison remains within the infected cell until it
disintegrates
◦ May cause typhoid fever & bacillary dysentery
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Exotoxins
◦ Poison is excreted by the cell into the surrounding
area
◦ May cause tetanus, gas gangrene, diphtheria and
scarlet fever
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Gram negative cell wall
Obligate intracellular pathogen
◦ Must live within a host cell
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Arthropod borne (vectors)
Cat scratch fever, trench fever (lice vector)
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Energy parasites – use ATP from host
Gram negative cell wall
Obligate intracellular pathogen
Transmission is aerosol or direct contact
Can cause pneumonia, inclusion
conjunctivitis, trachoma (blindness) as well as
sexually transmitted infection.
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Smallest of cellular microbes
No cell walls, so have many shapes
Gram stain ineffective because they have no
cell wall
May be free living or parasitic
Antibiotics that focus on inhibiting cell wall
synthesis are ineffective
Ex: Mycoplasmic pneumonia