Prokaryotes
PROKARYOTES.............................................................................................................................................. 1
PROKARYOTES.............................................................................................................................................. 3
STRUCTURE AND FUNCTION.....................................................................................................................................3
Shape:.............................................................................................................................................................3
Arrangement (e.g. chains or clumps of cells)..................................................................................................3
Size:.................................................................................................................................................................3
CELL ORGANIZATION...............................................................................................................................................3
Common features:..........................................................................................................................................3
Plasma Membrane:.........................................................................................................................................3
Structure of a Polar membrane Lipid:.............................................................................................................4
BACTERIA...................................................................................................................................................... 4
BACTERIAL MEMBRANE PROTEINS:............................................................................................................................4
Integral Proteins:............................................................................................................................................4
Peripheral proteins:.........................................................................................................................................4
BACTERIAL LIPIDS.................................................................................................................................................. 4
BACTERIAL CELL WALL............................................................................................................................................4
Cell Wall Functions:.........................................................................................................................................4
Peptidoglycan Structure (murein)...................................................................................................................5
Peptidoglycan as a drug target:......................................................................................................................5
Peptidoglycan as an enzyme target:...............................................................................................................5
Gram-Negative cell walls:...............................................................................................................................6
Gram-Negative Outer Membrane Permeability.............................................................................................6
Gram-Positive Cell Walls:................................................................................................................................6
Teichoic Acid Structure:...................................................................................................................................6
Periplasmic space of Gram-positive bacteria:................................................................................................7
Lipopolysaccharides (LPSs):.............................................................................................................................7
S Layers:..........................................................................................................................................................7
ARCHAEA...................................................................................................................................................... 8
MAIN GROUPS......................................................................................................................................................8
ARCHAEAL CELL ENVELOPES:....................................................................................................................................8
ARCHAEAL CELL WALLS..........................................................................................................................................8
Archaeal Cell Walls (differences from bacterial cell walls).............................................................................8
Archaeal Pseudomurein subunit composition................................................................................................8
ARCHAEAL MEMBRANES.........................................................................................................................................9
ARCHAEAL MOLECULAR BIOLOGY.............................................................................................................................9
Common properties to all Archaea:..............................................................................................................10
Summary:......................................................................................................................................................10
BACTERIAL AND ARCHAEAL CYTOPLASMIC STRUCTURES.............................................................................10
PROTOPLAST AND CYTOPLASM...............................................................................................................................10
CYTOSKELETON:.................................................................................................................................................. 10
NUCLEOID:.........................................................................................................................................................10
PLASMIDS:......................................................................................................................................................... 10
EXTERNAL STRUCTURES:........................................................................................................................................11
PILI AND FIMBRIAE:............................................................................................................................................. 11
FLAGELLA:..........................................................................................................................................................11
Bacterial Flagella:.........................................................................................................................................11
MICROSCOPY.............................................................................................................................................. 12
LIGHT & THE BENDING OF LIGHT:..........................................................................................................................12
LENSES:............................................................................................................................................................. 12
THE LIGHT MICROSCOPE.......................................................................................................................................12
The Bright-Field Microscope:........................................................................................................................12
1
, Prokaryotes
MICROSCOPE RESOLUTION....................................................................................................................................12
PREPARATION AND STAINING OF SPECIMENS............................................................................................................13
Fixation:........................................................................................................................................................13
Dyes and simple staining:.............................................................................................................................13
Differential Staining:.....................................................................................................................................14
Gram Stain: (only microbacteria stain red)..................................................................................................14
MICROBIAL REPRODUCTION STRATEGIES.................................................................................................... 15
BINARY FISSION...................................................................................................................................................15
CHROMOSOME REPLICATION AND PARTITIONING.......................................................................................................15
PROKARYOTIC GROWTH........................................................................................................................................15
The growth curve:.........................................................................................................................................15
* Unbalanced growth:..................................................................................................................................16
THE MATHEMATICS OF MICROBIAL GROWTH.............................................................................................................16
MEASUREMENT OF GROWTH RATE AND GENERATION TIME..........................................................................................17
MEASUREMENT OF MICROBIAL GROWTH.................................................................................................................17
Direct measurement of cell numbers:...........................................................................................................17
MICROBIAL NUTRITION............................................................................................................................... 19
MACROELEMENTS (MACRONUTRIENTS)....................................................................................................................19
MICRONUTRIENTS:...............................................................................................................................................19
REQUIREMENT FOR C, H AND O.............................................................................................................................19
GROWTH FACTORS:..............................................................................................................................................19
Classes of Growth factors:............................................................................................................................19
CULTURE MEDIA......................................................................................................................................... 20
Some Media components:............................................................................................................................20
CHEMICAL AND PHYSICAL TYPES OF CULTURE MEDIA:..................................................................................................20
FUNCTIONAL TYPES OF MEDIA:...............................................................................................................................20
General purpose............................................................................................................................................20
Enriched media.............................................................................................................................................20
Selective media.............................................................................................................................................21
Differential media.........................................................................................................................................21
INFLUENCE OF ENVIRONMENTAL FACTORS ON MICROORGANISM GROWTH...............................................21
TEMPERATURE.................................................................................................................................................... 21
OXYGEN CONCENTRATION.....................................................................................................................................21
THE BASIS FOR DIFFERENT OXYGEN SENSITIVITIES.......................................................................................................22
2
, Prokaryotes
The scope of Microbiology
- Study of things that are too small to see with the naked eye
- Prokaryotes = cellular organisms with no true nucleus
o Bacteria and Archaea
Prokaryotes
Structure and Function
- Prokaryotes differ from eukaryotes in size and complexity:
o Most lack internal membrane systems
o Term prokaryotes is becoming blurred
o This course will use term bacteria and archaea
- Prokaryotes divided into 2 domains:
o Bacteria and Archaea
Shape:
- Cocci (spherical)
o Streptococci – chains
o Staphylococci – grape like clusters
- Bacilli (rods)
o Coccobacilli – very short rods
- Vibrio’s – resemble rods, comma shaped
- Spirilla – rigid helices
- Spirochetes – flexible helices
- Filamentous
Arrangement (e.g. chains or clumps of cells)
- Determined by plane of division
- Determined by whether daughter cells separate after cell division or not
Size:
- Varies
Cell organization
Common features:
- Cell envelope is plasma membrane plus all layers outside of it (i.e. cell wall etc.)
- Cytoplasm (no organelles, no ER, no GA)
- External structures (fimbriae, flagella; some bacteria have a capsule or layer of slime)
Plasma Membrane:
- Encompasses cytoplasm
- Selectively-permeable barrier
- Interacts with external environment:
o Receptors for detection of and response to chemicals in surroundings
3
PROKARYOTES.............................................................................................................................................. 1
PROKARYOTES.............................................................................................................................................. 3
STRUCTURE AND FUNCTION.....................................................................................................................................3
Shape:.............................................................................................................................................................3
Arrangement (e.g. chains or clumps of cells)..................................................................................................3
Size:.................................................................................................................................................................3
CELL ORGANIZATION...............................................................................................................................................3
Common features:..........................................................................................................................................3
Plasma Membrane:.........................................................................................................................................3
Structure of a Polar membrane Lipid:.............................................................................................................4
BACTERIA...................................................................................................................................................... 4
BACTERIAL MEMBRANE PROTEINS:............................................................................................................................4
Integral Proteins:............................................................................................................................................4
Peripheral proteins:.........................................................................................................................................4
BACTERIAL LIPIDS.................................................................................................................................................. 4
BACTERIAL CELL WALL............................................................................................................................................4
Cell Wall Functions:.........................................................................................................................................4
Peptidoglycan Structure (murein)...................................................................................................................5
Peptidoglycan as a drug target:......................................................................................................................5
Peptidoglycan as an enzyme target:...............................................................................................................5
Gram-Negative cell walls:...............................................................................................................................6
Gram-Negative Outer Membrane Permeability.............................................................................................6
Gram-Positive Cell Walls:................................................................................................................................6
Teichoic Acid Structure:...................................................................................................................................6
Periplasmic space of Gram-positive bacteria:................................................................................................7
Lipopolysaccharides (LPSs):.............................................................................................................................7
S Layers:..........................................................................................................................................................7
ARCHAEA...................................................................................................................................................... 8
MAIN GROUPS......................................................................................................................................................8
ARCHAEAL CELL ENVELOPES:....................................................................................................................................8
ARCHAEAL CELL WALLS..........................................................................................................................................8
Archaeal Cell Walls (differences from bacterial cell walls).............................................................................8
Archaeal Pseudomurein subunit composition................................................................................................8
ARCHAEAL MEMBRANES.........................................................................................................................................9
ARCHAEAL MOLECULAR BIOLOGY.............................................................................................................................9
Common properties to all Archaea:..............................................................................................................10
Summary:......................................................................................................................................................10
BACTERIAL AND ARCHAEAL CYTOPLASMIC STRUCTURES.............................................................................10
PROTOPLAST AND CYTOPLASM...............................................................................................................................10
CYTOSKELETON:.................................................................................................................................................. 10
NUCLEOID:.........................................................................................................................................................10
PLASMIDS:......................................................................................................................................................... 10
EXTERNAL STRUCTURES:........................................................................................................................................11
PILI AND FIMBRIAE:............................................................................................................................................. 11
FLAGELLA:..........................................................................................................................................................11
Bacterial Flagella:.........................................................................................................................................11
MICROSCOPY.............................................................................................................................................. 12
LIGHT & THE BENDING OF LIGHT:..........................................................................................................................12
LENSES:............................................................................................................................................................. 12
THE LIGHT MICROSCOPE.......................................................................................................................................12
The Bright-Field Microscope:........................................................................................................................12
1
, Prokaryotes
MICROSCOPE RESOLUTION....................................................................................................................................12
PREPARATION AND STAINING OF SPECIMENS............................................................................................................13
Fixation:........................................................................................................................................................13
Dyes and simple staining:.............................................................................................................................13
Differential Staining:.....................................................................................................................................14
Gram Stain: (only microbacteria stain red)..................................................................................................14
MICROBIAL REPRODUCTION STRATEGIES.................................................................................................... 15
BINARY FISSION...................................................................................................................................................15
CHROMOSOME REPLICATION AND PARTITIONING.......................................................................................................15
PROKARYOTIC GROWTH........................................................................................................................................15
The growth curve:.........................................................................................................................................15
* Unbalanced growth:..................................................................................................................................16
THE MATHEMATICS OF MICROBIAL GROWTH.............................................................................................................16
MEASUREMENT OF GROWTH RATE AND GENERATION TIME..........................................................................................17
MEASUREMENT OF MICROBIAL GROWTH.................................................................................................................17
Direct measurement of cell numbers:...........................................................................................................17
MICROBIAL NUTRITION............................................................................................................................... 19
MACROELEMENTS (MACRONUTRIENTS)....................................................................................................................19
MICRONUTRIENTS:...............................................................................................................................................19
REQUIREMENT FOR C, H AND O.............................................................................................................................19
GROWTH FACTORS:..............................................................................................................................................19
Classes of Growth factors:............................................................................................................................19
CULTURE MEDIA......................................................................................................................................... 20
Some Media components:............................................................................................................................20
CHEMICAL AND PHYSICAL TYPES OF CULTURE MEDIA:..................................................................................................20
FUNCTIONAL TYPES OF MEDIA:...............................................................................................................................20
General purpose............................................................................................................................................20
Enriched media.............................................................................................................................................20
Selective media.............................................................................................................................................21
Differential media.........................................................................................................................................21
INFLUENCE OF ENVIRONMENTAL FACTORS ON MICROORGANISM GROWTH...............................................21
TEMPERATURE.................................................................................................................................................... 21
OXYGEN CONCENTRATION.....................................................................................................................................21
THE BASIS FOR DIFFERENT OXYGEN SENSITIVITIES.......................................................................................................22
2
, Prokaryotes
The scope of Microbiology
- Study of things that are too small to see with the naked eye
- Prokaryotes = cellular organisms with no true nucleus
o Bacteria and Archaea
Prokaryotes
Structure and Function
- Prokaryotes differ from eukaryotes in size and complexity:
o Most lack internal membrane systems
o Term prokaryotes is becoming blurred
o This course will use term bacteria and archaea
- Prokaryotes divided into 2 domains:
o Bacteria and Archaea
Shape:
- Cocci (spherical)
o Streptococci – chains
o Staphylococci – grape like clusters
- Bacilli (rods)
o Coccobacilli – very short rods
- Vibrio’s – resemble rods, comma shaped
- Spirilla – rigid helices
- Spirochetes – flexible helices
- Filamentous
Arrangement (e.g. chains or clumps of cells)
- Determined by plane of division
- Determined by whether daughter cells separate after cell division or not
Size:
- Varies
Cell organization
Common features:
- Cell envelope is plasma membrane plus all layers outside of it (i.e. cell wall etc.)
- Cytoplasm (no organelles, no ER, no GA)
- External structures (fimbriae, flagella; some bacteria have a capsule or layer of slime)
Plasma Membrane:
- Encompasses cytoplasm
- Selectively-permeable barrier
- Interacts with external environment:
o Receptors for detection of and response to chemicals in surroundings
3
