Microbiology

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Microbiology

• Chapter 1

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Part I

• Introduction to Microbiology

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Scope of Microbiology

• Microbes
• Life forms which require magnification for
  viewing
• Ubiquitous
• Each group has a distinct set of biological
  characteristics
• Single celled vs. multi-celled
• Prokaryotic vs. eukaryotic
• Cell wall vs. no cell wall
• Autotrophic vs. heterotrophic
• Cellular vs. acellular

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Prokaryotic vs. Eukaryotic
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Assigning Characteristics

• Bacteria
• Protozoa
• Fungi
• Algae
• Helminths
• Viruses

Assign common characteristics to each group
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Mycobacterium tuberculosis. Acid fast bacteria
(shown in pink) like this causes TB and leprosy.
Light blue is Staph epi, a common bacteria cocci
which inhabits the Skin. Not a common pathogen
Schistosoma (worms) at two different stages of
development liver Disease and other symptoms
(Top) Coccidioidomycosis Arthrospores (Bottom)
Development of Arthrospores Into spherule in
lung tissue Fungal Infection of the lung
Staphylococcus Aureus Gram positive
bacteria Staph infections and MRSA
Trypanosoma Eukaryotic pathogen African Sleeping
Sickness
Treponema pallidum Bacterial spirochete Causes
syphilis
Herpes Virus
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Size Comparisons
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Part II

• Historical Figures in Microbiology

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Superstition of Microbiology

• Spontaneous generation
• For thousands of years people believed that
  living things arose from vital forces present in
  non living matter
• Mushrooms appearing on rotting wood
• Afflicted people were thought to be cursed
• Controversy between
• Abiogenesis and biogenesis

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First Look at Microbes

• In the 1600s
• Robert Hooke (English) reported that living
  things were composed of little boxes or cells
• Antonie van Leeuwenhoek construction microscopes
  which could magnify 300X
• Described microorganisms that he observed in
  teeth scrapings rain water

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Abiogenesis vs. Biogenesis

• Franceso Redi
• He wanted to ascertain whether maggots arose from
  some vital force of the meat or were offspring
  of flies

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Abiogenesis vs. Biogenesis

• Conclusions of Redis Experiment
• This and related experiments proved that complex
  animals such as insects and mice develop through
  biogenesis
• However, meat leaf out but covered with gauze
  would still rot
• Therefore, the idea that simpler organism could
  arise from abiogenesis was still accepted

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Proving that Microbes Are Present in Dust
Particles

• Jablots vs. Needhams Experiment
• Jablots experiment supported the idea that
  microbes are present in the air

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Proving that Microbes Are Present in Dust
Particles

• However, support for Jablots experiment faltered
  when Needhams results were reported
• Needham performed the same experiment with mutton
  gravy
• Microbial growth was in both containers
• What do you think happened here?

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Proving that Microbes Are Present in Dust
Particles

• These disputes would be put to rest with Louis
  Pasteurs work

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Pasteurization

• Pasteur also demonstrated that spoilage bacteria
  could be killed by heat that was not hot enough
  to evaporate the alcohol in wine. This
  application of a high heat for a short time is
  called pasteurization

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Listers Work

• English physician advanced the idea of antisepsis
  in health care setting 1860s
• Dressed wounds with carbolic acid (phenol)
• Reduced deaths among patients by 2/3
• Listerine Mouthwash

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Kochs Postulates

• 1876 Robert Koch provided proof that a bacterium
  causes anthrax and provided the experimental
  steps, postulates, used to prove that a specific
  microbe causes a specific disease
• Koch was a physician and Pasteurs young rival

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Kochs Postulates
Take scraping and plate on agar
Mouse dies with sores
A heterogeneous population of bacteria Grow
which one is the causative agent
Isolate all different strains and types and
inject into healthy mice and see which
mice develop similar phenotype and symptoms
Take a sample again from mice which died of same
symptoms and isolate the causative agent again
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Kochs Postulates
A sequence of experimental steps to relate a
specific microbe to a specific disease
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Kochs Postulates
Used to prove the specific causative agent of
an infectious disease
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Jenners Work

• Observed that milkmaids did not acquire smallpox
• Milkmaids were exposed to chronic low doses of
  cowpox and therefore acquired specific immunity
• 1796 Jenner inoculated a person with cowpox virus
  and found this person was then protected against
  acquiring small pox
• This protection is known as immunity
• Called vaccinatin from vacca for cow

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Alexander Flemings Work

• In 1928 Fleming discovered the first antibiotic
  by accident
• He observed that Penicillium fungus secreted a
  substance which killed bacteria
• Explain why a fungus would do this
• In 1940s penicillin was tested clinically and
  mass produced

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Germ Theory of Disease

• All of these aforementioned people and others
  helped give rise to the germ theory of disease
• Germ Theory states that microorganisms can invade
  other organisms and cause disease
• Before this many time politics and religion would
  spur on erroneous theories

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Part III

• Introduction to Disease

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Chronic vs. Infectious Disease

• Chronic
• Disease which persists over a long period of time
• Atherosclerosis, cancer heart failure
• Infectious
• Organism enters and tissues grows
• Bacterial Prokaryotic
• Viral Acellular
• Protozoan Eukaryotic
• Causes symptoms in patients

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Conquering Infectious Disease

• The triumph over infectious disease?
• Antibiotics discovered in 1940s
• Vaccinations routinely delivered in the 1950s
  through today
• Eradication of polio and small pox
• But then
• MRSA
• Drug resistant TB
• HIV
• Ebola
• Avia Flu
• And more

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Conquering Infectious Disease

• What went wrong?
• Medical advances
• Older and sicker people live longer
• More susceptible to garden variety microbes
• Population is more mobile
• Emerging diseases
• Encroachment of humans into wild habitat
• Rapid evolution and biochemical changes to
  microbes
• Microbes have a quick generation time

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Top Causes of Death
United States Deaths Worldwide Deaths
1. Heart Disease 696,950 1. Heart Disease 8.12 x 106
2. Cancer 557,270 2. Stroke 5.51 x 106
3. Stroke 162,670 3. Res infection 3.88 x 106
4. Chronic LRD 124,800 4. Cancer 3.33 x 106
5. Accidents 106,740 5. HIV/AIDS 2.78 x 106
6. Diabetes 73,250 6. Chronic LRD 2.75 x 106
7. Flu Pneumonia 65,680 7. Diarrheal disease 1.80 x 106
8. Alzheimer disease 58,870 8. Tuberculosis 1.57 x 106
9. Kidney problems 40,970 9. Malaria 1.27 x 106
10.Septicemia 33,865 10. Accidents 1.19 x 106
Stands for lower respiratory disease Infectious
Diseases are shown in red
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Infectious Disease Statistics
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Part IV

• Taxonomy Biological Classification

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Organizing Life

• Classification
• Orderly arrangement of organisms into groups that
  indicate evolutionary relationships
• Nomenclature
• Assigning names to various taxonomic rankings
• Identification
• Correct placement of organism into taxonomic
  scheme

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Taxonomy

• Origins of organizing biological life
• Carl von Linne or Linnaeus 1701 1778
• System of recognizing and defining properties of
  living organism followed by the placement into
  specific slots
• Grouped according to similar properties
• Grouped according to evolutionary relatedness
• Constantly being revised and refined

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Taxonomy
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Nomenclature

• Scientists use a standard binomial system
• Overseen by an international group
• Verify that standard procedures were followed
• Ascertain the uniqueness of each name
• Make sure no other name exists

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Nomenclature

• Staphylococcus aureus
• Staphule bunch of grapes
• Aureus golden
• Campylobacter jejuni
• Kampylos curved
• Bakterion little rod
• Jejunum section of small intestine
• Giardia lamblia
• Alfred Giard French microbiologist
• Vilem Lambl Bohemian physician

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Evolution Phylogeny

• Evolution
• All new species originate from preexisting
  species
• Closely related organism have similar feature due
  to evolution from common ancestral forms
• Phylogeny
• Tree of life
• Classification based on evolutionary relatedness

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Whittakers System
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Whittakers System

• Although used for many years this system has
  problems in terms of evolutionary relatedness
• Kingdom Protista
• Autotrophs heterotrops are groups together
• Archaea
• Although these organisms are prokaryotic they are
  more closely related to eukaryotic cells

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Solution to Whittakers Tree

• Biologist no longer group organisms into a 5
  kingdom system
• Currently a three domain system
• Many original kingdoms still work
• Plants, animals, fungi
• However, Kingdom Protista Kingdom Monera have
  been extensively reorganized into many different
  kingdoms

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Three Domain System