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Title: Introduction%20and%20Overview%20of


1
Introduction and Overview of General
Microbiology Lecture 1 What is Microbiology?
2
In Microbiology- We Study Microbes
  • What are microbes?
  • Micro- means small
  • By definition, we study small organisms
  • those that we cannot see with the naked eye.
    (limit of resolution of eye 0.2 mm)

3
Biological Classification The Five
Kingdoms (Whittaker) (based on morphological
features)
Uni or multicellular Eukaryotic
Eukaryotic Unicellular
Bacteria Archaea
Prokaryotic
Unicellular
4
Eukarya
(Eu)Bacteria
Archaea
(Make up other 4 Kingdoms)
(Makes up 1 Kingdom Monera)
Biological Classification Today 3 Domain
(Superkingdoms) System (Woese) (Based mainly on a
gene sequence (DNA))
5
Binomial Nomenclature
  • Carolus (Carl) Linnaeus 1750s probably not
    the first person to do this but certainly made it
    popular and acceptable
  • Homo sapiens Homo is the genus (pl. genera),
    name can only be used once always capitalized
  • sapiens species epithet never capitalized and
    can be used many times
  • Both the genus and species epithet make up the
    species name

6
What organisms do Microbes include?
  • 1) Bacteria (Prokaryotes)
  • 2) Viruses
  • 3) Fungi (yeasts, molds)
  • 4) Protista (protozoans)
  • 5) Algae
  • 6) Helminths

7
2) Protista Eukaryotic Most Unicellular
1) Bacteria (Eu)bacteria Archaea Archeabacteria Pr
okaryote Unicellular
3) Fungi Eukaryotic Uni- or multicellular
8
4) Helminths Multicellular eukaryotes Roundworms F
latworms
5) Viruses Alive? Organisms? Neither prokaryotic
or Eukaryotic
6)Algae Many are microscopic We are really
talking about Eukaryotic Types
9
Types of Microorganisms
  • Prokaryotes Bacteria
  • Unicellular organisms
  • No compartmentalization
  • No organelles
  • No nucleus
  • Cell wall
  • All reproduce by binary fission or budding
  • Ribosomes
  • Plasma membrane
  • Circular DNA chromosome
  • Plasmids

Small in size 1000 X magnification 200 nm to 1 mm
Tremendous diversity
10
Prokaryotes 2 Main Groups
More in Chapter 4
1) Bacteria or Eubacteria (True
Bacteria) Non-archaea prokaryotes Most have
Peptidoglycan in the cell wall
2) Archaea Possibly Ancient (hence the
name) Different structure physiologies Harsh
environments Extremophiles No peptidoglycan in
their cell wall
11
Main Types of Bacteria
  • Four main types - based on morphology (shape)

coccus (sphere-shaped)
bacillus (rod-shaped)
(pl. cocci) strep- staph- and diplo-
(pl. bacilli) (sub-categories do exist
(cocco-bacilli, vibrios))
spirillum (pl. spirilla) helical flattened
s-shaped non-flexible cell wall
spirochete (corkscrew shaped) (flexible cell wall)
12
Protista
  • Eukaryotic microbes
  • Most are unicellular
  • Have no cell wall - only plasma membrane
  • May have pellicle
  • Most are motile - distinguished by type of
    motility
  • Pseudopods - cytoplasmic extensions, false
    foot
  • (amoebas)
  • Flagella - whip like propellers (flagellates)
  • Cilia - short hair-like structures coating
    entire surface
  • (ciliates)

13
Fungi
  • Eukaryotic organisms, extensive subcellular
  • compartmentalization
  • Can be single or multicellular organisms (yeasts
    mold hyphae)
  • Cell wall is composed of chitin
  • Can replicate either asexually (binary fission)
    or
  • sexually (mating)
  • Obtain nutrients from surroundings
  • Parasites or saprophytes

14
Types of Fungi
Multi-cellular (Molds) Penicillium
Unicellular (Yeast) Saccharomyces cerevisiae
Multi-cellular Mushrooms
15
Algae
  • Can be either unicellular or multicellular
  • Photosynthetic eukaryotes
  • Cellulose cell wall
  • Exist in many environments (water and land)
  • Photoautotrophs
  • Consumed by animals as food

16
Viruses
  • Acellular
  • Simple virus
  • Capsid (protein)
  • Nucleic acid (DNA or RNA)

Electron microscope 10 nm 200 nm
17
History of Microbiology
  • Two major pioneers
  • Antonie van Leeuwenwoek
  • first to visualize bacteria- created the
    simple microscope (1660s)
  • Robert Hooke devised the compound microscope
    (1660s) and coined the term cell
  • This turned out to be the beginning of the end of
    spontaneous generation (superstition)

18
Spontaneous Generation
  • Life arising from dead matter
  • Maggots would appear on spoiled meat
  • Fungi, insects, millipedes, and snakes found in
    rotten logs
  • Was believed life spontaneously generated from
    the
  • decomposing food

19
First Evidence Against Spontaneous Generation
(life from non-life)
Francesco Redi - 1668
Maggots only appeared if flask was open!
Spoiled Meat
Did not exclude the possibility of spontaneous
generation of bacteria
20
Proponents of Spontaneous Generation Battle Back!
  • John Needhams broth experiments - 1745
  • Boiled broth was devoid of life
  • Days later - teeming with microorganisms
  • Argued that microbes could arise spontaneously
    from
  • non-living mater
  • Lazzaro Spallanzanis modification - 1765
  • Only uncovered broth contained microorganisms
  • Proponents argued that fresh air was required

21
The Final Blow to the Spontaneous Generation
Hypothesis
  • Louis Pasteur - 1861

22
Significant Advances in Microbiology
  • 1864 - Fermentation and Pasteurization - Louis
    Pasteur
  • Discovered source of fermentation
  • Yeast convert sugar to alcohol
  • Bacteria cause spoiling - convert alcohol to
    vinegar
  • Found heating perishables prevented spoiling
    kills
  • bacteria

23
Significant Advances in Microbiology
  • 1876 - The Germ Theory of Disease proved correct
  • Robert Koch developed Kochs Postulates (4)
  • Anthrax decimating cattle industry
  • 1) Find evidence of a microbe in all infected
    individuals
  • 2) Isolate rod-shaped bacterium from infected
    individual
  • 3) Introduce bacterium to healthy individual and
    get same disease
  • 4) Can reisolate the same bacterium from diseased
    individuals

24
Significant Advances in Microbiology
  • 1796 - First successful vaccination - Edward
    Jenner
  • Smallpox epidemics prevalent
  • Cowpox caused similar disease in cattle mild
  • disease in humans
  • Jenner found infecting humans with cowpox
  • protected against smallpox infection
  • Due to antigenic similarity between two viruses
    (body recognizes these viruses as the same in
    some ways)

25
Significant Advances in Microbiology
  • 1928 - Discovery of Antibiotics - Alexander
    Flemming
  • Plate contaminated with
  • Penicillium
  • Zone of inhibition
  • Killed Streptococcus
  • Called substance penicillin

26
Fields of Microbiology
  • Bacteriology - study of bacteria (includes
    Bacteria and Archaea)
  • Mycology - study of fungi
  • Parasitology - study of parasitic protozoa and
    worms
  • Virology - study of viruses
  • Immunology - study of the host response to
    infection
  • Protozoology general study of protozoa
  • Algalogy study of algae (for some might include
    cyanobacteria)

27
Lecture 1 questions?
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