Title: Archaebacteria and Eubacteria
1Archaebacteria 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.
6Archaebacteria
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.
9Extreme 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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12Eubacteria
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.
14Cyanobacteria 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.
21Endospore
- Bacteria can survive unfavorable conditions by
producing an endospore.
22Shapes of Bacteria
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26Penicillin, 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.
29In 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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33Is this gram stain positive or negative?
Identify the bacteria.
34Is 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.