Post on 01-Jun-2015
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CHAPTER 11: THE PROKARYOTES
Domains Bacteria and Archaea
The Prokaryotic Groups◦Prokaryotes are divided into two groups◦ Bacteria
◦Archaea
◦See difference on Page 291 figure 10.6
The Proteobacteria
◦ Includes most G(-) bacteria and are thought to
have arisen from a common photosynthetic
organism
◦Largest group of bacteria
Alphaproteobacteria
◦ Typically can grow at a low
level of nutrients
◦Unusual morphology including
buds or stalks
◦ Stalks that are used to adhere to
a surface are called
prosthecae
◦Name comes from the
mythological Greek god
Proteus who could morph into
many shapes
◦Alpha-
◦Beta-
◦Gamma-
◦Delta-
◦Epsilon-
◦Alpha- are very important in
agriculture because many
of these bacteria can fix
nitrogen and can live in
symbiosis with plants and
humans
Azosprillium
◦Rickettsia and Chlamydia
are obligate intracellular
parasites
◦They can only reproduce
within a mammalian cell
◦They are commonly
transmitted within insect
bites and ticks
◦ Spotted fever, typhus, Rocky
Mountain spotted fever
◦Caulobacter bacteria are found
in low-nutrient aquatic
environments
◦ They have prosthecae because
of the constant changing flow of
water
◦Bartonella is a gram (-) bacillus that causes
cat scratch fever
Betaproteobacteria
◦There are many similarities
between alpha- and beta-
◦Often use ammonia,
hydrogen gas, or methane
◦Pathogenic bacteria are
considered
betaproteobacteria
◦Spirillum is found in fresh water and has
polar flagella and is an aerobic organism
◦ Sphaerotilus are sheathed,
G(-) bacteria found in
sewage
◦ The sheath is a protective
layer which provides
protection and a source of
nutrient accumulation
◦Bordetella is the group of bacteria responsible for
whooping cough. It is nonmotile, aerobic, and
G(-)
◦Neisseria are aerobic,
G(-), cocci that live in
mucosal membranes
of mammals
◦Pathogens in this groups
cause gonorrhea and
meningitis.
Gammaproteobacteria
◦Largest
subgroup of
Proteobacteria
◦Pseudomonas is aerobic, G(-) rods with
polar flagella
◦Very common in soil
◦ Infects urinary tract, burns, wounds
◦ Some species have evolved to grow
inside some antiseptics
◦Moraxella is a group of bacteria that cause
conjunctivitis
◦Vibrio bacteria are facultatively
anaerobic, G(-) slightly curved rods
◦Cause of cholera and gastroenteritis
◦Salmonella is potentially
pathogenic
◦They inhabit intestine tracts
of many animals
◦Causes Typhoid fever and
salmonellosis
Deltaproteobacteria
◦ Include bacteria that prey on other bacteria.
They are predators.
◦Desulfovibrio are obligately anaerobic bacteria
that form hydrogen sulfide
◦Can be found in the intestinal tracts of humans
◦Myxococcus leave behind a slime trail and
they get their energy by lysing other
bacteria
Epsilonproteobacteria
◦ Slender G(-) rods that are helical or vibrio and are
microaerophile
◦Heliobacter is the
most common
cause of peptic
ulcers and causes
stomach cancer
GRAM + BACTERIA
Gram Positive Bacteria
◦Can be divided into two groups
◦High G+C ratio
◦Low G+C ratio
◦G = guanine
◦C = cytosineDNA
Research
◦Clostridium
◦Epulopiscium
◦Staphylococcus
◦Lactobacillus
◦Listeria
◦Propionibacterium
◦Leptospira
◦Fusobacterium
◦Where does the bacteria live?◦Shape or arrangement?◦Disease it causes (if it does)?◦Growth conditions?◦ Interesting fact?
Clostridium
Epulopiscium
Staphylococcus
Lactobacillus
Listeria
Propionibacterium
Leptospira
Fusobacterium
DOMAIN ARCHAEA
◦Cell walls lack peptidoglycan (like eukaryotes)
◦Halophiles- organisms that can survive a high salt content
◦Methanogens- organisms that produce methane
◦Hyperthemophiles- organisms that can survive and thrive in high temperatures
MICROBIAL DIVERSITY
◦Though many prokaryotes have
been discovered, scientists have
hardly reached the tip of the
iceberg when it comes to
discovering the vast number of
organisms still out there
◦Maybe YOU will be the next
scientist to discover a new
bacterium!