Microbiology – Chapter 1

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Microbiology


Chapter 1

Microbiology
-

The science that studies very small living
things

Usually requires a magnification tool


the microscope

Some organisms are large though


Helminths


worms

Sub groups of Microbes we will study

Bacteria

Archaea

Fungi

Protozoans

Algae

Viruses

Multicellular animal parasites


Helminths

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Bacteria

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Fungi

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Protozoans


Giardia



Ameba

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Viruses

Bacteriophage


Avian Flu

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Helminth

Tapeworm


Ascaris round worm

Microbiology


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Various disciplines of study within
microbiology:

Bacteriology, Mycology, Parisitology,
Immunology,

Epidemiology,

Biotechnology

Virology

Environmental Microbiology

Bioremediation

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Chapter 1

Historical review of the Science of
Microbiology

Robert Hook


1665


Englishman, used a
primitive compound (two magnifying lenses)

microscope, reported that life’s smallest
units were little boxes


Cells
, his work

started the process of the development of
the
Cell theory
of life

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Hook’s microscope

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Antoni Van Leeuwenhoek

1673
-

probably the first person to observe living
cells with a simple microscope, amateur
scientist, ground his own lenses and
described what we know today as bacteria


rod shaped , spiral shaped , etc.
“animalcules”


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Antoni Van Leeuwenhoek

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Francesco Redi


1668


opposed the
prevailing theory of Spontaneous Generation,

maggots in meat , He used covered jars to
show that maggots came from flies

strong
evidence against spontaneous generation

Now we teach the theory of Biogenesis


Life comes from Life

But issue of Spontaneous Generation was
actively believed for many more years

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Francesco Redi

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Edward Jenner
is credited with first
vaccine


in
epidemics of smallpox during the late 1700’s he observed
that milk maids didn’t get the disease, cattle had a similar

disease


cowpox
, milk maids had cow pox lesions, but
not small pox, he purposefully took scrapings from cowpox
blister and scraped a 8 year old volunteer. With the
material


child got mild illness but not small pox,


Vaccination
comes from Latin word “vacca” meaning cow.
Jenner laid the foundation for Pasteur’s later work with
other vaccinations.

(Vaccinia virus similar to Variola smallpox virus, today a
possible bioterror weapon


genetically engineered
variola?)

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Jenner and vaccination

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Pasteur


French sceintist that dealt the death blow to the
spontaneous generation theory.


He devised the ingenious curved necked flasks that
prevented contaminated air from reaching boiled beef broth


the broth remained uncontaminated even though
exposed to the air


He was very lucky


no
endopores
present, or it would
have failed

(resitant to boiling)

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1. He developed process we call Pasteuriztion


he heated wine to kill contaminating microbes


cured sick wine (today we heat treatment to kill
pathogens in milk also)

2. He proved that fermentation was caused by a
microbe


yeast

3. He developed vaccines for rabies and anthrax.
Vaccines led to immunity to diseases that routinely
killed many people, used to help people long
before they understood how they even worked
(science of Immunology)

4. He began the revolution in science that led to
the
Golden Age of

Microbiology
(from 1857
-
1914)

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Robert Koch
-

Developed
Koch’s postulates


important technique
for determining the

actual microbial cause agent of a disease


more later, German,
contemporary of Pasteur, several very important contributions

1. He discovered the tuberculosis bug (tubercle bacillus,

Mycobacterium tuberculosis)

2. He discovered the cause of anthrax (Bacillus anthracis)


from

blood of dead cattle, cultured bacteria in pure culture,

injected bacteria in live cattle and they died, then again

cultured the bacteria in pure culture. This led to the


establishment of a procedure for determining microbial

cause of disease (see p. ____
-
for modern application of

Koch’s postulates)

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Koch’s postulates

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Koch’s and Pasteur’s work helped
establish the “Germ Theory of Disease”
-

that

microorganisms cause disease (in
people, animals, and even plants
)

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Iwanowski
1892
-

Discovered that plant disease
can be caused by small organisms that

were so small they passed through filters , Tobacco
mosaic virus (TMV) was later

identified as the cause
-

beginning of virology
(Today we have discovered new and

weird things like
viroids, prions
) See next slide

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Paul Ehrlich
, German doctor, wanted to find a
“magic bullet” an agent that would kill

the disease agent without hurting the patient (see
the “Coming plague” video, part 1)

1. Developed
Salvarsan
, “salvation from

syphilis”agent

2. This was an arsenical


arsenic compound, that

was effective against syphilis


Antimicrobial agent, medicine to treat a

microbial disease, it was chemical


chemotherapy

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Syphilis spirochete:
T. pallidum

Paul Ehrlich

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Joseph Lister


1860’s, English surgeon that
applied ideas of the germ theory to surgery,
remembered the work of Semmelweis in Hungary
in the 1840’s, if a Dr. would wash their hands
childbed fever was prevented. He knew that
phenol would kill bacteria; put 2 and 2 together
and treated wounds with phenol
-

and no infection
(phenol is the basic agent of today’s


Lysol)

1. First antiseptic use in surgery, chemicals used

as agents

on tissue before surgery


(tissue treated with an antimicrobial agent



antiseptic, betadine) disinfectants are

chemicals,

used on a surface

2. Also proved that microbes cause surgical

infections

(today’s scourge

MRSA)

Semmelweis


Lister


Antisepsis in surgery

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Alexander Fleming
-

Scottish physician and bacteriologist
-

1928

Observed mold growing on a bacteria culture, there was a ring of
clearing around the mold where the bacteria didn’t grow, the mold
was later found to be a Penicillium species and the naturally
secreted chemical was called penicillin, an
antibiotic

1. Antibiotics are
natural
agents

2. Synthetic drugs are chemicals produced in labs (sulfas)

3. Problems with them
-

toxicity, resistance, allergic reactions

4. Fleming’s work
-

shelved until early WWII, sulfas were failing,

needed penicillin to cure battle field wounds

5. Now have thousands of antibiotics and synthetics (and a

significant problem


resistance)

Flemming and Penicillium


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Salk
-

Polio vaccine, 1950’s polio was a scary
epidemic, Salk developed a vaccine by

treating the virus with formalin (IPV) inactivated
polio virus

Sabin
1963 live Polio virus vaccine, attenuated

altered virus, OPV
-
oral polio vaccine

The work done on polio revolutionized the science
of virology and we are seeing

the results today in advances with Hepatitis and
HIV viral infections
-

tissue

culture
and other techniques

Avery and Macleod, DNA is genetic material


Watson and Crick, DNA, 1953


DNA Double helix


Double Helix

Salk; IPV


Sabin, OPV


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Jacob and Monod


1965 Did research on RNA and
protein synthesis in bacteria
-

last

necessary step in understanding how genetics works on a
cellular level (Replication,

Transcription, Translation


protein synthesis


expression
of traits)

Modern science thrives today only on the laid foundation of
thousands of men and

women who did mundane routine and often boring lab
science. Don’t forget that we are

here today because we stand on the shoulders of Giants


who were people just like you

and me. (Who are the Giants today? CDC, USAMRID,
young Joe or Mary the graduate

student?, maybe you?)

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Classification, Taxonomy, Binomial
Nomenclature
-

Yucchy!!!!! No one likes
it. Just do it!!!

The Classification of Living
Things



Living organisms are assigned to groups
based upon their similarities.



Systematics

is the discipline of
identifying and classifying organisms.

Domains


The highest


largest category, recent addition


3 domains


1. Archaea


ancient “bacteria”, unicellular like
bacteria, also simple cell structure (prokaryote


no
nucleus) but have distinct metabolism (chemistry)
allowing them to exist in “extreme” environments


2. Bacteria


unicellular, prokaryote, found
everywhere (Old kingdom name


Monera)


3. Eukarya


unicellular to multicellular, complex and
organized cells with nuclei and organelles
(mitochondria)

Domain Archaea


Archaea are single
-

celled organisms that
lack a membrane
-
bound nucleus.
-

Prokaryote



Archaea can be found
in environments that
are too hostile for
other life forms.

Domain Bacteria


Bacteria are single
-

celled organisms that
lack a membrane
-
bound nucleus.
(Prokaryote also)



Bacteria are found
almost everywhere on
the planet Earth.


Domain Eukarya


The cells of all eukaryotes have a membrane
-
bound nucleus. Members of the Domain
Eukarya are further categorized into one of
four
Kingdoms
. (know these kingdoms)

Microbiology


Check your notes; Older 5 kingdom
scheme is still widely used


Monera


bacteria (Prokaryotic)


Protista


Protozoans (Eukaryotic)


Fungi
-

yeast, molds, etc. (Eukaryotic)


Plant


photosynthetic producers
(Eukaryotic)


Animals


heterotrophic consumers
(Eukaryotic)


Categories of Classification

Domain


Kingdom



Phylum




Class




Order





Family






Genus







Species


Categories of Classification

Domain
-

Dumb


Kingdom
-

King



Phylum
-

Philip




Class


Came




Order
-

Over





Family
-

For






Genus
-

Good







Species
-

__

Spaghetti?


Categories of Classification



Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species


Least inclusive

Most inclusive

Categories of Classification

Scientific Names


Binomial (two name) Genus first and first letter
capitalized, then species not capitalized. If
written or typed


either underline or italicize


Genus name, species name


Homo sapiens
-

italicized


Homo troglodytis

(Your EX?)


underlined


Canis familiaris



Your puppy (except poodles)


Felis domesticus


Your Kitty (some strange people
have to have
Felis leo

or
Felis tigris
)


Canis latrans



Invites your kitty over for lunch


Canis lupus

-

____________? guess

Know for test


3 domains Archaea, Bacteria, Eukarya


4 Eukarya Kingdoms


Protista


Protozoans like Ameba and
Paramecium (producers and consumers)


Fungi


yeasts, molds, mushrooms
(consumers)


Plants


complex producers, trees, grasses


Animals


complex consumers

Classification of Bacteria


Somewhat different: a clinical rapid ID is
often important when trying to find
causative agent of a disease


Bergey’s manual: Manual is in lab for a
reference when doing unknown


Developed on 1940’s for grouping bacteria
according to standard diagnostic lab
techniques available at the time (such as
Grams stain)

Classification of Bacteria


Gram +

cocci



Gram
-

bacilli

Classification of Bacteria


Gram
-

Spirochete


Gram + bacilli

Classification of Bacteria


The manual divides bacteria into 4 groups
or divisions on the basis of their Cell Wall


1. Gram + (stain violet)


2. Gram
-

(destain, and are counterstained
pink or reddish color)


3. Bacteria that lack a cell wall (mycoplasma)


4. organisms that have a cell wall lacking
“peptidoglycan” (archaeobacteria


Now
called “Archaea”

Classification of Bacteria


More modern methods now used:


1. DNA studies, genomics, gene probes


2. using Bacterial viruses “bacteriophages”


3. Serology


antibody


antigen reactions (like
blood typing)



Examples:
Salmonella typhi


Salmonella typhimurium


Azotobacter vinelandii

12837


E. coli
0157H7 nasty strain of E. coli