Transcript A. Cell Biology of Bacteria

MICROBIOLOGY
Cell Biology of
Bacteria
Instructor
Terry Wiseth
Northland Community & Technical College
BACTERIAL
FACTS
Scientists have named and
described more than 4,000
species of bacteria
New ones are discovered so
rapidly, however, they estimate
the number of unknown species
in the millions
Almost every time scientists
search among bacteria in a soil
or water sample, they discover
previously unknown species
2
BACTERIAL FACTS
The overwhelming majority of bacteria
are harmless to humans or animals
Bacteria get virus infections
Antibiotics and other bacteria-derived
materials are the basis of a $50 billion
annual market for biotechnology products
Oil spills are cleaned primarily by
bacteria that feed on oil
3
BACTERIAL
FACTS
About 10 percent of human body weight
and 50 percent of the content of the
human colon is made up of bacteria
(Escherichia coli)
each square centimeter of human skin
hosts an average of 100,000 bacteria
Washing removes many, but they
reproduce so quickly--doubling every 20
minutes--that the population is restored in
hours
4
BACTERIAL
FACTS
So many bacteria live underground that
their total weight has been estimated at
100 trillion tons
If these microbes were spread over
Earth's land surface, they would make a
layer five feet thick
5
CLASSIFICATION
Microbes
organisms smaller than the eye can
detect
bacteria
fungi
protists
virus
6
CELL TYPES
Prokaryotes
Eukaryotes
Viruses
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PROKARYOTES
Monera
bacteria
1 micron
diameter
8
EUKARYOTES
algae, protozoa
and fungi
5 - 100 microns
9
VIRUSES
neither prokaryotes nor eukaryotes
informational parasites
each kingdom has its own associated
viruses
10
MICROBIAL SIZE
Virus 0.05 to 0.1 microns
Bacteria 0.5 to 1.5 microns
Red blood cell 5 microns
Sperm 60 microns
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MICROBIOLOGY
disease
agriculture
food and drink
chemical products
basic research
biotechnology
12
PROKARYOTES
VS
EUKARYOTES
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
14
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
15
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
16
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
17
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
18
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
19
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
20
CELL CHARACTERISTICS
Prokaryote
Eukaryote
Chromosome
Single circular
Chromosome location
Nucleoid
(no membrane)
Nucleolus Absent
Chromosome
Paired linear
Chromosome location
Nucleus
(membrane present)
Nucleolus Present
Extra chromosomal
DNA in Plasmid
Extra chromosomal
DNA in Mitochondria
and Chloroplast
Cellular Respiration in
Mitochondria
Undulating flagella,
cilia, amoeboid
movement
Ribosome in
organelles
Cellular Respiration in
Cell membrane
Locomotion
Rotating flagella
Ribosome in
cytoplasm
21
BACTERIAL SHAPE
BACTERIA
SHAPE
range in size from 0.20 to 2.0 micrometers
in diameter
1) Bacillus
2) Spiral
3) Cocci
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BACILLUS
1) Bacillus
Rod shape
Diplobacilli
Two bacilli together
Streptobacilli
Chains of bacilli
Vibrios
curved rods
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BACILLUS
Escherichia coli
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SPIRAL
2) Spiral
spirillia
Spiral, helical, corkscrew shape that
is rigid
spirochete
the organism is flexible and undulating
26
COCCI
3) Cocci
spherical shaped
diplococci
remain in pairs
streptococci
chains
staphylococci
clusters
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COCCI
Moraxella catarrhallis
inhabitant of the
upper respiratory
tract, especially the
nasal cavity
notice some are in
the diploid state
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BACTERIAL
CELL WALL
CELL
MEMBRANE
phospholipid bilayer
integral and peripheral proteins
embedded
maintains the selective permeability of
the cell
has respiratory enzymes
30
CELL WALL
cell wall surrounds the cell membrane
Structurally, the wall is necessary for
1) maintain shape
2) counter osmotic pressures
3) attachment sites for bacteriophages
4) platform for surface appendages
31
CELL WALL
1) Maintaining the cell's characteristic
shape
the rigid wall compensates for the
flexibility of the phospholipid
membrane and keeps the cell from
assuming a spherical shape
32
CELL WALL
2) Countering the effects
of osmotic pressure
the strength of the wall
is responsible for
keeping the cell from
bursting when the
intracellular osmolarity
is much greater than
the extracellular
osmolarity
33
CELL WALL
3) Providing
attachment sites for
bacteriophages
teichoic acids
attached to the outer
surface of the wall
are like landing pads
for viruses that
infect bacteria
34
CELL WALL
4) Providing a rigid platform for
surface appendages
flagella, fimbriae, and pili all
emanate from the wall and extend
beyond it
35
CELL WALL
cell walls of all bacteria are not identical
cell wall composition is one of the most
important factors in bacterial species
analysis and differentiation
clinically
contributes to ability to cause disease
site of action of antibiotics
There are two major
types of walls:
Gram-positive
Gram-negative
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GRAM POSITIVE
Has a thick peptidoglycan layer
90% of the Gram-positive cell wall is
comprised of peptidoglycan
two types of teichoic acids
37
GRAM POSITIVE
1) Lipoteichoic acid
on the surface, embedded in the
peptidoglycan layer
linked to the cytoplasmic membrane
38
GRAM POSITIVE
2) Wall teichoic acid
on the surface
linked to only the peptidoglycan layer
39
GRAM POSITIVE
40
GRAM NEGATIVE
cell wall of Gram-negative bacteria is
much thinner
comprised of only 20% peptidoglycan
have two unique regions which surround
the outer plasma membrane:
periplasmic space
lipopolysaccharide layer
41
GRAM NEGATIVE
a thin peptidoglycan layer
an outer membrane attached to the
peptidoglycan layer by lipoproteins
42
GRAM NEGATIVE
the outer membrane is made of protein,
phospholipid and lipopolysaccharide
the lipid portion is embedded in the
phospholipid
The lipid is toxic
43
GRAM NEGATIVE
The cell wall has channels called
Porins for the transport of low
molecular weight substances
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GRAM NEGATIVE
periplasmic space
between the cytoplasmic membrane
and the cell wall
hydrolytic enzymes
antibiotic
inactivating
enzymes
transport
proteins
45
GRAM NEGATIVE
Strong negative charge assists in:
evading phagocytosis
evade the complement system
provides increased barrier to:
antibiotics, lysozymes, detergents
46
GRAM NEGATIVE
provides more attachment sites for:
virus
harmful substances
more susceptible to mechanical breakage
lipid A endotoxin is toxic to host
47
CELL WALL
the cell wall is not a
regulatory structure
like the cell
membrane
though it is porous, it
is not selectively
permeable and will let
anything pass that
can fit through its
gaps
48
EXTRACELLULAR
MATRIX
attached to the cell wall
made of polysaccharide or polypeptide,
or a combination of both
form a viscous layer
capsule
slime layer
49
CAPSULE
Capsule
thick, structured and adheres strongly to
the cell wall
Adhere to surfaces to form colonies
Antiphagocytic
Antigenic
Protect the organism
from dehydration
50
CAPSULE
51
SLIME LAYER
Slime layer
disorganized and loosely attached to
the cell wall
Staphylococcus mutans
causes dental caries
52
MOVEMENT
Flagellum
Made of the protein flagellin
rotation is for swimming towards an
attractant
water is as viscous as syrup for a
bacteria
able to move 50 microns/sec
100X bacterial body length/sec
fish able to swim only 10X body
length/sec
53
MOVEMENT
Axial Filaments
found in Spirochetes
similar to flagella
attached throughout the body length
54
PILI
made of the protein pilin
virulence factors
project from the cell surface
Conjugation Pili
for the transfer of extrachromosomal
DNA between donor and recipient
55
FIMBRIAE
used for attachment to surfaces
more numerous than pili
56
CYTOPLASMIC
STRUCTURES
Nucleoid
area of concentrated
DNA
no nuclear membrane
The DNA is single
circular
double stranded
without proteins
57
CYTOPLASMIC
STRUCTURES
Ribosomes
cytoplasmic, not
attached to
organelles
Plasmids
Extrachromosomal loops of DNA
some code for drug resistance
toxins
58
TYPICAL
BACTERIA
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ENDOSPORES
Metabolically inactive
may produce endospores under
environmental stress
lack of water
lack of nutrients
severe temperature changes
Clostridium
Bacillus
60
ENDOSPORES
Spores can be dormant for many years
can survive
extreme heat
desiccation
radiation
toxic chemicals
61
ENDOSPORES
when conditions become favorable they
revert to an active state
Spore germination is activated by heat in
the presence of moistures
62
END
CELL BIOLOGY OF
BACTERIA