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Archaebacteria and Eubacteria

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Title: Archaebacteria and Eubacteria


1
Archaebacteria and Eubacteria
2
  • Bacteria are of immense importance because of
    their rapid growth, reproduction, and mutation
    rates, as well as, their ability to exist under
    adverse conditions.
  • The oldest fossils known, nearly 3.5 billion
    years old, are fossils of bacteria-like
    organisms.

3
  • Bacteria can be autotrophs or hetertrophs.
  • Those that are classified as autotrophs are
    either photosynthetic, obtaining energy from
    sunlight or chemosynthetic, breaking down
    inorganic substances for energy .

4
  • Bacteria classified as heterotrophs derive energy
    from breaking down complex organic compounds in
    the environment. This includes saprobes,
    bacteria that feed on decaying material and
    organic wastes, as well as those that live as
    parasites, absorbing nutrients from living
    organisms.

5
  • Depending on the species, bacteria can be aerobic
    which means they require oxygen to live
  • or
  • anaerobic which means oxygen is deadly to them.

Green patches are green sulfur bacteria.  The
rust patches are colonies of purple non sulfur
bacteria.  The red patches are purple sulfur
bacteria.
6
Archaebacteria
7
  • Methanogens
  • These Archebacteria are anaerobes. They make
    methane (natural gas) as a waste product. They
    are found in swamp sediments, sewage, and in
    buried landfills. In the future, they could be
    used to produce methane as a byproduct of sewage
    treatment or landfill operation.

8
  • Halophiles
  • These are salt-loving Archaebacteria that grow
    in places like the Great Salt Lake of Utah or
    salt ponds on the edge of San Francisco Bay.
    Large numbers of certain halophiles can turn
    these waters a dark pink. Pink halophiles contain
    a pigment very similar to the rhodopsin in the
    human retina. They use this visual pigment for a
    type of photosynthesis that does not produce
    oxygen. Halophiles are aerobes, however, and
    perform aerobic respiration.

9
Extreme halophiles can live in extremely salty
environments. Most are photosynthetic autotrophs.
The photosynthesizers in this category are purple
because instead of using chlorophyll to
photosynthesize, they use a similar pigment
called bacteriorhodopsin that uses all light
except for purple light, making the cells appear
purple.
10
  • Thermophiles
  • These are Archaebacteria from hot springs and
    other high temperature environments. Some can
    grow above the boiling temperature of water. They
    are anaerobes, performing anaerobic respiration.
  • Thermophiles are interesting because they contain
    genes for heat-stable enzymes that may be of
    great value in industry and medicine. An example
    is taq polymerase, the gene for which was
    isolated from a collection of Thermus aquaticus
    in a Yellowstone Park hot spring. Taq polymerase
    is used to make large numbers of copies of DNA
    sequences in a DNA sample. It is invaluable to
    medicine, biotechnology, and biological research.
    Annual sales of taq polymerase are roughly half a
    billion dollars.

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12
Eubacteria
13
  • Cyanobacteria
  • This is a group of bacteria that includes some
    that are single cells and some that are chains of
    cells. You may have seen them as "green slime" in
    your aquarium or in a pond.
  • Cyanobacteria can do "modern photosynthesis",
    which is the kind that makes oxygen from water.
    All plants do this kind of photosynthesis and
    inherited the ability from the cyanobacteria.

14
Cyanobacteria were the first organisms on Earth
to do modern photosynthesis and they made the
first oxygen in the Earth's atmosphere.
15
  • Bacteria are often maligned as the causes of
    human and animal disease. However, certain
    bacteria, the actinomycetes, produce antibiotics
    such as streptomycin and nocardicin.

16
  • Other Bacteria live symbiotically in the guts of
    animals or elsewhere in their bodies.
  • For example, bacteria in your gut produce vitamin
    K which is essential to blood clot formation.

17
  • Still other Bacteria live on the roots of certain
    plants, converting nitrogen into a usable form.

18
  • Bacteria put the tang in yogurt and the sour in
    sourdough bread.
  • Saprobes help to break down dead organic matter.
  • Bacteria make up the base of the food web in many
    environments.

Streptococcus thermophilus in yogurt
19
  • Bacteria are prokaryotic and unicellular.
  • Bacteria have cell walls.
  • Bacteria have circular DNA called plasmids
  • Bacteria can be anaerobes or aerobes.
  • Bacteria are heterotrophs or autotrophs.
  • Bacteria are awesome!

20
  • Bacteria can reproduce sexually by conjugation or
    asexually by binary fission.

21
Endospore
  • Bacteria can survive unfavorable conditions by
    producing an endospore.

22
Shapes of Bacteria
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Penicillin, an antibiotic, comes from molds of
the genus Penicillium Notice the area of
inhibition around the Penicillium.
27
  • Penicillin kills bacteria by making holes in
    their cell walls. Unfortunately, many bacteria
    have developed resistance to this antibiotic.

28
  • The Gram stain, which divides most clinically
    significant bacteria into two main groups, is the
    first step in bacterial identification. 
  • Bacteria stained purple are Gram - their cell
    walls have thick petidoglycan and teichoic acid.
  • Bacteria stained pink are Gram their cell walls
    have have thin peptidoglycan and
    lipopolysaccharides with no teichoic acid.

29
In Gram-positive bacteria, the purple crystal
violet stain is trapped by the layer of
peptidoglycan which forms the outer layer of the
cell. In Gram-negative bacteria, the outer
membrane of lipopolysaccharides prevents the
stain from reaching the peptidoglycan layer. The
outer membrane is then permeabilized by acetone
treatment, and the pink safranin counterstain is
trapped by the peptidoglycan layer.
30
  • The Gram stain has four steps
  • 1. crystal violet, the primary stain followed
    by
  • 2. iodine, which acts as a mordant by forming a
    crystal violet-iodine complex, then
  • 3. alcohol, which decolorizes, followed by
  • 4. safranin, the counterstain.

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Is this gram stain positive or negative?
Identify the bacteria.
34
Is this gram stain positive or negative?
Identify the bacteria.
35
  • Gram staining tests the bacterial cell wall's
    ability to retain crystal violet dye during
    solvent treatment.
  • Safranin is added as a mordant to form the
    crystal violet/safranin complex in order to
    render the dye impossible to remove.
  • Ethyl-alcohol solvent acts as a decolorizer and
    dissolves the lipid layer from gram-negative
    cells. This enhances leaching of the primary
    stain from the cells into the surrounding
    solvent.
  • Ethyl-alcohol will dehydrate the thicker
    gram-positive cell walls, closing the pores as
    the cell wall shrinks. 
  • For this reason, the diffusion of the crystal
    violet-safranin staining is inhibited, so the
    bacteria remain stained. 
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