Chapter 1. The Microbial World and You

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Chapter 1. The Microbial World and You
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What are microbes?
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Naming Microorganisms
Who is credited with our current system of naming
organisms? What language and why? Species
Genus specific epithet
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Examples of binomial nomenclature
Panthera leo Panthera leo spelaea
Eulemur coronatus
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Examples of binomial nomenclature
Tyrannosaurus rex
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Its the same with microorganisms
Escherichia coli
Mycobacterium tuberculosis
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Classification of Microorganisms
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Classification of Microorganisms
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History of Microbiology
Robert Hooke Micrographica - 1665
. . I could exceedingly plainly perceive it to be
all perforated and porous, much like a
Honey-comb, but that the pores of it were not
regular. . . . these pores, or cells, . . . were
indeed the first microscopical pores I ever saw,
and perhaps, that were ever seen, for I had not
met with any Writer or Person, that had made any
mention of them before this. . .
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History of Microbiology
Antony van Leeuwenhoek, tradesman, 1665
Bacteria Nematodes and rotifers Protists and
protistan parasites Sperm cells Blood cells
and circulation
. . . my work, which I've done for a long time,
was not pursued in order to gain the praise I now
enjoy, but chiefly from a craving after
knowledge, which I notice resides in me more than
in most other men. And therewithal, whenever I
found out anything remarkable, I have thought it
my duty to put down my discovery on paper, so
that all ingenious people might be informed
thereof. Antony van Leeuwenhoek. Letter of June
12, 1716
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The Controversy over Spontaneous Generation
What is Spontaneous Generation? Abiogenesis? A
nd Biogenesis?
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Evidence Pro and Con

• 1668 Francisco Redi filled six jars with
  decaying meat.

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Evidence Pro and Con

• 1745 John Needham put boiled nutrient broth into
  covered flasks.

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Evidence Pro and Con

• 1765 Lazzaro Spallanzani boiled nutrient
  solutions in SEALED flasks.

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Evidence Pro and Con

• 1861 Louis Pasteur demonstrated that
  microorganisms are present in the air.

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The Theory of Biogenesis

• Pasteurs Swan necked flask kept microbes out but
  let air in.

Figure 1.3
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The Golden Age of Microbiology 1857-1914
Fermentation and Food Spoilage lead to the Germ
Theory of Disease and Pasteurization
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The Golden Age of Microbiology 1857-1914
Germ Theory of Disease and Kochs Postulates
1835 Silkworm disease has natural causes, not
supernatural
1840s Hand-washing reduces deaths in hospitals
1860s Lister uses chemical disinfectant to
reduce deaths after surgery
1835 Koch shows that anthrax caused by
bacteria standardizes method of investigating
disease Kochs postulates
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The Golden Age of Microbiology 1857-1914
Germ Theory of Disease and Kochs Postulates

• Isolate a specific microbe in pure culture from
  an organism sick with the disease
• 2. Inoculate a healthy organism with microbes
  from the pure culture
• 3. Healthy organism must get sick with the same
  signs and symptoms as the first organism
• 4. Same microbe must be isolated from second
  organism as was isolated from the first

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The Golden Age of Microbiology 1857-1914
Vaccination - 1796
Jenner Why dont the milkmaids get smallpox?
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The Golden Age of Microbiology 1857-1914
The birth of Chemotherapy
What is chemotherapy?
1910 Ehrlich synthetic drug salvarsan 1928
Fleming accidentally discovers penicillin 1930s
synthetic sulfonamides
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Modern Developments
Includes Bacteriology Mycology Parasitology
anthrax
Wheat rust
Bot fly
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Modern Developments
Also, Immunology Virology Recombinant DNA
Technology
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Microbes and Human Welfare
Ecology and the Biogeochemical Cycles
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Microbes and Human Welfare
Bioremediation
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Microbes and Human Welfare
Biological Insecticides
Bacillus thuringiensis most insects, esp.
mosquitos
Nematodes - insects
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Microbes and Human Welfare
Genetic Engineering
Gene inserted in plant or animal to produce
medicinal products (Pharming) Ex.
Blood-clotting proteins for haemophiliacs
insulin for diabetics alpha-antitrypsin for a
type of liver disease. Gene therapy gene
inserted directly in human body via integrating
virus or bacteria. Ex. HIV virus can be used as a
carrier.  
http//www.scienceandsociety.emory.edu/GMO/GMO20a
nd20Medicine.htm
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Microbes and Disease
Normal Microbiota - a mutualistic interaction

• Normal microbiota prevent growth of pathogens.
• Normal microbiota produce growth factors such as
  folic acid and vitamin K.
• Resistance is the ability of the body to ward off
  disease.
• Resistance factors include skin, stomach acid,
  and antimicrobial chemicals.

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Microbes and Disease
Vaccines today

• Inactivated
• Attenuated
• Subunit

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Infectious Diseases

• When a pathogen overcomes the hosts resistance,
  disease results.
• Emerging Infectious Diseases (EID) New diseases
  and diseases increasing in incidence

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Emerging Infectious Diseases

• West Nile encephalitis
• West Nile Virus
• First diagnosed in the West Nile region of Uganda
  in 1937.
• Appeared in New York City in 1999.

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Emerging Infectious Diseases

• Bovine Spongiform
• Encephalopathy
• Prion
• Also causes Creutzfeldt-Jakob disease (CJD)
• New-variant CJD in humans related to cattle fed
  sheep offal for protein.

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Emerging Infectious Diseases

• Escherichia coli O157H7
• Toxin-producing strain of E. coli
• Fist seen in 1982
• Leading cause of diarrhea worldwide.

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Emerging Infectious Diseases

• Invasive group A Streptococcus
• Rapidly growing bacteria cause extensive tissue
  damage (necrotizing fasciitis).
• Increased incidence since 1995

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Emerging Infectious Diseases

• Ebola hemorrhagic fever
• Ebola virus
• Causes fever, hemorrhaging, and blood clotting
• First identified near Ebola River, Congo
• Outbreak every few years

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Emerging Infectious Diseases

• Hantavirus pulmonary syndrome
• Hantavirus
• Fist identified in 1951 in Korea as cause of
  hemorrhagic fever and named for Hantaan River
• A new disease involving respiratory symptoms was
  seen in the U.S. in 1995
• The U.S. virus, called Hantavirus Sin Nombre
  virus, probably came to the U.S. with rats around
  1900

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Emerging Infectious Diseases

• Acquired immunodeficiency syndrome (AIDS)
• Human immunodeficiency virus (HIV)
• First identified in 1981.
• Worldwide epidemic infecting 40 million people
  14,000 new infections everyday.
• Sexually transmitted disease affecting males and
  females.
• In the U.S., HIV/AIDS in people 13-24 years of
  age 44 are female and 63 are African American.

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Emerging Infectious Diseases

• Anthrax
• Bacillus anthracis
• In 1877, Koch proved B. anthracis causes anthrax.
• Veterinarians and agricultural workers are at
  risk of cutaneous anthrax.
• In 2001, dissemination of B. anthracis via mail
  infected 22 people.