UNIT 2 Flashcards
Study of microorganisms
Microbiology
Increase in cell number
Microbial growth
Splits into two cells
Binary fission
Time required for a cell to divide
Generation time
Cells form an initial outgrowth (a bud)
Budding
Microbes that grow and multiply in or on culture media
Culture
A group of descendants of an original cell
Colony
Aka: AXENIC
Pure culture
Pure culture
Contains a single microbial species
6 definition of terms
- Microbial growth
- Binary Fission
(Generation Time) - Budding
- Culture
- Colony
- Pure Culture
3 Physical requirements for growth
- Temperature
- pH
- Osmotic Pressure
Category in Temperature
- PSYCHROPHILES
- PSYCHOTROPHS
- MESOPHILES
- THERMOPHILES
It is sensitive to temperatures over 20’
PSYCHROPHILES
optimum growth at 20’C to 30’C
PSYCHROTROPHS
Optimum growth at 25’C to 40’C
MESOPHILES
EXTREME THERMOPHILES
grown at 80’C or higher
Optimum growth oa 50’C to 60’C
THERMOPHILES
Category in pH
- Acidophiles
- Neutrophils
- Alkaliphiles
Lactobacillus acidophilus
Acidophiles
Grow at pH 5.4 to 8.5
Neutrophiles
Vibrio cholerae
Alkaliphines
brown at high pH (7 to 12)
Alkaliphiles
Category in Osmotic Pressure
Obligate Halophiles
Facultative Halophiles
Aka: Extreme Halophiles
Osmotic pressure
Does not require high salt concentration for growth
Facultative Halophiles
Requires very high concentration 20-30%
Tolerates 2-15% salt concentration
Facultative Halophiles
Grow at a very low pH (0.1 to 5.4)
Acidophiles
7 Chemical requirements for growth
A. Carbon
B. Nitrogen
C. Sulfur
D. Phosphorus
E. Others
F. Oxygen
G. Carbon Dioxide
Category of Carbon
Chemoheterotrophs
Chemoautotrophs
Organic carbon sources
Chemoheterotrophs
Inorganic energy sources
Chemoautotrophs
May need to consume other living organisms to live
Chemoheterotrophs
Primary carbon source is carbon dioxide
Chemoautotrophs
Nitrogen
Makes up to 14% of dry cell weight
Sulfur
Used to form proteins and some vitamins
Used to form DNA, RNA, ATP and phospholipids
Phosphorus
Others
K
Mg
Ca
Fe
Cu
Mo
Zn
Growth requirement for aerobic microorganisms
Oxygen ; sources : atmosphere water
5 category of oxygen
Obligate aerobes
Facultative anaerobes
Obligate anaerobes
Aerotolerant anaerobes
Micro-aerophiles
It requires oxygen to live.
Obligate aerobes
Obligate aerobes
Mycobacterium tubercolosis
It can use oxet Feb, but can grow in its absence
Facultative anaerobes
Facultative anaerobes
Escherichia coli
Can’t use oxygen and is harmed by the presence of toxic forms of oxygen
Obligate anaerobes
Obligate anaerobes
Clostridium tetani
Can’t use oxygen but can grow in its absence
Aerotolerant anaerobes
Aerotolerant anaerobes
Streptococcus pneumoniae
Micro-aerophiles
Helicobacter pylori
Requires oxygen at low
Micro-aerophiles
Oxygen in anaerobes
O2—metabolism—toxic— Bacterial
Product. Death.
O2-OH- O2+ H2O2
Breaks down hydrogen peroxide
Peroxidase
Catalase
Converts hydrogen peroxide to water & oxygen
Converts superoxide to oxygen & hydrogen peroxide
Superoxide dismutase
Bacterial growth
Lag phase
Lag phase
Stationary phase
Death or decline phase
Lag phase
No increase in number of living bacterial cells
Log phase
Exponential increase in number of living bacterial cells
Stationary phase
Plateau in number of living bacterial cells; rate of cell division and death roughly equal
Death or decline phase
Exponential decrease in number of living bacterial cells
Superoxide free radical
Superoxide dismutase
Peroxide anion
Catalase
Peroxidase
Carbon Dioxide
CO2-loving
Carbon dioxide
Candle jar
CO2 generating packet
Require Increase concentration of CO2 and lower levels of O2
Carbon dioxide
Substance containing nutrients in which cells or microorganisms can be grown; may be solid, liquid or gel
Culture media
3 Characteristics of culture media
Contains appropriate nutrients
Sterile
Incubated at appropriate temperature
Act of introducing microorganisms or suspension of microorganisms into a culture medium
Inoculation
Microbial cells added to a medium in order to start a culture
Inoculum
3 Category of culture media
Solid media
Liquid media
Semisolid media
Nutrient material that contains a solidifying agent
Solid media
Nutrient material that contains <1% solidifying agent
Semisolid media
Nutrient material that last solidifying agent
Liquid media
Liquid medium in a tube, bottle or flask
Broth
Applicable if high concentration of bacteria is desired
Broth
Loose cap
Bacteria is above
Obligate aerobes
Bacteria is in the lower part of the tube
Obligate anaerobes
More bacteria in the top part of the tube and lesser at the bottom
Facultative anaerobes
The bacteria is scattered in the tube
Aerotolerant anaerobes
Agar plate
Difficult to transport and store
Allows for isolation and examination of colonies
Agar plate
For microorganisms that prefer O2
Agar Deep
Inoculating needle is used to stab the solid medium
Agar deep
For easy storage and transportation
Agar slant
Agar slant
Tube of solid medium at an angle for higher surface area
Cannot be degraded by most bacteria
Agar
Some species of red algae
Gracilaria compressa
Gelidium cartilagineum
Gelidium amansii
Unbranched polysaccharide obtained from the cell walls of some species of red algae
Agar
Melts above 95’c
agar
Does not solidify until it reaches 40’C
Agar
6 Types of culture media
All purpose media
Selective media
Differential media
Enrichment media
Chemically defines media
Complex media
Microorganisms requiring special culture technique
Mycobacterium tubercolosis
Treponema pallidum
Obligate parasites
Influenza virus
Mycoplasma
Exact components are difficult to estimate because of complex ingredients
Complex media
Prepared from pure chemical substances of known composition and concentration
Chemically defined media
Favors growth of a particular microorganism over others by providing essential nutrients
Enrichment media
Used for differentiating between bacteria by using an identification marker for a specific type of microorganisms
Differential media
Allows growth of desired microorganism while suppressing the growth of unwanted microorganisms
Selective media
Has multiple effect
All purpose media
For general purposes of preservation, isolation, storage of cultures and antibiotic sensitivity test
All purpose media
Difference between binary fission from mitosis
No mitotic spindle form
generation time E.coli
30 to 180 mins
generation time M. tuberculosis
12 hours
T. pallidum
33 hours in rabbit testes
M. leprae
10 days in armadillos
Cocci synthesize new cell walls
septal region
Rod shape bacteria
Logarithmic representation of bacterial growth
2^n
the initial outgrowth
a bud
other name of pure culture
axenic culture
how the surface of the colony appears
texture
Texture types
smooth
glistening
mucoid
slimy
dry
powdery
flaky
Transparency
Transparent
Translucent
Opaque
You can see through them
Transparent
Light pass through them
Translucent
solid-appearing
opaque
Intracellular pigments
color/pigmentation
Many bacteria do not produce any pigment and appear _________
white or gray
Magnifying tool
Colony counter
Dissecting microscope
Colony size
Punctiform <1 mm
Small 1-2 mm
Medium 3-4 mm
Large >5 mm
Colony forms
Circular
Rhizoid
Irregular
Filamentous
Colony Margin
Entire
Undulate
Lobate
Filamentous
Curled
Colony elevation
Flat
Raised
Convex
Pulvinate
Umbonate
Rely on organic compounds as source of food to provide energy and carbon
Heterotrophs
Mesophile/Mesophilic temperature
20 to 40 degrees celsius
Body Temperature
37
Room temperature
Room temperature
The lowest temperature at which an organism is able to conduct metabolism
Minimum growth temperature
Temperature at which an organism’s metabolic activities produce the highest growth rate
optimum growth temperature
The highest temperature at which an organism continues to metabolize
maximum growth temperature
when temperature exceed maximum growth temperature, the organism’s _________
protein are permanently denatured and dies
P S Y C H R O P H I L E S other name
cryophiles
sensitive to temperatures over 20 ̊C
optimum growth at
15 ̊C or below
P S Y C H R O P H I L E S
− optimum growth at 20 ̊C to 30 ̊C
P S Y C H R O T R O P H S
− optimum growth at 25 ̊C to 40 ̊C
M E S O P H I L E S
− optimum growth at 50 ̊C to 60 ̊C
T H E R M O P H I L E S
P S Y C H R O T R O P H S Other name
Cold-tolerant bacteria or archaea
grow at 80 ̊C or higher
Extreme Thermophiles
M E S O P H I L E S other name
moderate temperature-loving
T H E R M O P H I L E S other name
Heat-loving
Extreme Thermophiles Example
Geogemma barosii
Geogemma barosii
85 to 121
2 hours in 130
Can destroy most microbes
> 60 degrees
slow microbial growth
50 to 60
rapid microbial growth; produce toxins
25 to 50
grow at very low pH (0.1 to 5.4)
A C I D O P H I L E S
Organs with low pH
Vagina and stomach
the causative agent of peptic ulcer
Helicobacter pylori
A C I D O P H I L E S example
Lactobacillus acidophilus
− grow at pH 5.4 to 8.5
N E U T R O P H I L E S
Lactobacillus produce
lactic acid
− grow at high pH (7 to 12)
A L K A L I P H I L E S
Most bacteria, protozoa, and pathogens grow best at what pH
Neutral
A L K A L I P H I L E S example
− Vibrio cholerae
cholera
− Alkaligenes faecalis
− Agrobacterium spp.
Pressure difference needed to stop the flow of solvent across a semipermeable membrane
Osmotic pressure
require very high salt conc. 20 to 30%
O B L I G A T E
H A L O P H I L E S
O B L I G A T E
H A L O P H I L E S
another name
extreme halophiles
strict halophiles
Can survive month in dry conditions due to the ability of its cell wall to retain water
Mycobacterium tuberculosis
− do not require high salt conc. for growth
− tolerates 2-15% salt concentration
F A C U L T A T I V E
H A L O P H I L E S
Salt-water principle
Water follows salt
Sodium attracts water
No net movement of water
Cells in isotonic solution
Shrink because of the net movement of water out of the cell
Cell in hypertonic solution
Undergo gain of water
Cells in hypotonic solution
Solute concentration inside and outside are the same
Isotonic solution
Have higher solute concentration than inside the cell
Hypertonic solution
Has a lower solute concentration
Hypotonic solution
Hypo comes from
Latin word under or low
− organisms that derive energy from organic carbon sources
− may need to consume other living organisms to
live
C H E M O H E T E R O T R O P H S
Organisms that obtain energy by the oxidation of electron donors in their environment
Chemotrophs
Organism that cannot manufacture its own food by carbon fixation and therefore derives its intake from other sources of organic carbon, mainly plant or animal matter
Heterotroph
Some bacteria can reduce nitrogen gas t
ammonia
S U L F U R sources
proteins,
hydrogen sulfide,
sulfates
Sulfur is used to synthesize sulfur-containing amino acids and vitamins like
Thiamine - Vitamin B1
Biotin - Vitamin H
used to form DNA, RNA, ATP, and phospholipids
P H O S P H O R U S
P H O S P H O R U S sources
Inorganic
phosphate salts,
Buffers (from culture medium)
phospholipids are found in _______
cell membranes of bacteria
Growth requirement for aerobic microorganisms
O X Y G E N
F A C U L T A T I V E
A N A E R O B E S
has ________ enzymes that allow toxic forms of oxygen to be neutralized
catalase
SOD (superooxide dismutase)
M I C R O -
A E R O P H I L E S
example
Helicobacter pylori
Campylobacter jejuni
Toxic forms of oxygen
Hydrogen peroxide
Superoxide radicals
converts superoxide to oxygen & hydrogen peroxide
Superoxide dismutase:
converts hydrogen peroxide to water & oxygen
Catalase:
Used for cell wall synthesis of gram-positive bacteria
Calcium
CULTURE MEDIA common ingredient
Peptone
Beef extract
Yeast extract
Distilled water
agar
The manner in which the inoculum is spread out into the cultured medium
Streaking
A G A R is the ____________ obtained from the cell walls of some species of red algae
Unbranched polysaccharide
some species of red algae
i. Gracilaria compressa
ii. Gelidium cartilagineum
iii. Gelidium amansii
Who first used agar
Robert Koch
Another solidifying agent
Gellan gum
Inoculating techniques
Stabbing
Stab and streak
Streaking
Irish moss (Red Algae)
Chondrus crispus
maybe done in media with dilute agar concentration
motility test
useful in demonstrating motility of bacteria
SEMISOLID MEDIA:
For general purposes of
preservation, isolation, storage of
cultures and antibiotic sensitivity
tests
ALL - P U R P O S E
M E D I A
ALL - P U R P O S E
M E D I A
examples
− Peptone water
− Nutrient broth
− Nutrient agar
− Bismuth Sulfite Agar
Allows growth of desired
microorganism while suppressing
the growth of unwanted
microorganism
S E L E C T I V E
M E D I A
S E L E C T I V E
M E D I A
example
− Saboraud’s dextrose agar
− Brilliant green agar
− Thayer-Martin agar
− Lowenstein Jensen Media
pH 5.6 discourages bacterial growth
for fungi
Saboraud’s dextrose agar
inhibits G+ bacteria and allows for the growth of G- salmonella
Brilliant green agar
for the growth of Neisseria gonorrheae
Thayer-Martin agar
Used to isolate Salmonella typhi
Bismuth Sulfite Agar
Used to isolate Mycobacterium tuberculosis
Lowenstein Jensen Media
Used for differentiating between
bacteria by using an identification
marker for a specific type of
microorganism
D I F F E R E N T I A L
M E D I A
D I F F E R E N T I A L
M E D I A
examples
− Mannitol salt agar
− MacConkey agar
− Blood agar
Mannitol salt agar
Staphyloccocus aureus -> halophile
MacConkey agar
Salmonella typhi
Uses hemolytic reaction
Used to distinguish bacteria that destroy red blood cells
Blood agar
Blood agar usually contains
sheep or horse blood
contains 7.5 % sodium chloride
Both selective and differential
has a pH indicator
Mannitol salt agar
Mannitol fermentation
pink to yellow positive
consider as complex, selective, and differential media
contains bile salt, and crystal violet that inhibits the growth of g+ bacteria
use lactose
MacConkey Agar
The growth in _______ indicates _______ , while _______ does not
pink; lactose utilization; yellow
Lactose fermenters examples
Enterobacter spp
Citrobacter spp
Klebsiella spp
Lactose fermenters will produce
acid
test the ability of an organism to produce hemolysin, enzyme that damage/lyse red blood cells
Blood agar media
Blood agar media members
Staphylococcus
Streptococcus
Enterococcus
Partial hemolysis
Alpha hemolysis
Complete hemolysis
Beta hemolysis
No hemolysis
Gamma hemolysis
the destruction of red blood cells
hemolysis
Alpha hemolysis examples
Streptococcus pneumoniae
Streptococcus mutans
Beta hemolysis examples
Staphylococcus aureus
Streptococcus pyogenes
Listeria ivanovii
Gamma hemolysis examples
Escherichia coli
Klebsiella pneumoniae
Enterococcus faecalis
Favors growth of a particular
microorganism over others by
providing essential nutrients
E N R I C H M E N T
M E D I A
E N R I C H M E N T
M E D I A
examples
− Chocolate agar
− Loeffler’s medium
− Brain heart infusion agar
complex or particular nutrient requirement
fastidious organism
Chocolate agar example
Haemophilus influezae
Haemophilus influezae
Haemophilus influezae
Brain heart infusion agar examples
Streptococci
Pneumococci
Meningococci
Made up of lysed RBCs
Chocolate agar
Haemophilus influenzae
Pneumonia and sepsis
Prepared from pure chemical
substances of known composition
and concentration
C H E M I C A L L Y
D E F I N E D
M E D I A
C H E M I C A L L Y
D E F I N E D
M E D I A
example
− Peptone water
− Modified Korthof’s medium
− Firm agar
The exact components are difficult to
estimate because of complex
ingredients
C O M P L E X
M E D I A
C O M P L E X
M E D I A
example
− Nutrient agar
− Trypticase soy agar
− Eosin methylene blue agar
use to culture most chemoheterotrophic microorganism
C O M P L E X
M E D I A
Eosin methylene blue agar is used for
Isolation of the fecal coliforms (E.coli)
Eosin methylene blue agar contains lactose and dyes _______ and _______
Eosin and methylene blue
Microorganism that cannot grow in culture media
Obligate parasites
SPECIAL CULTURE TECHNIQUES armadillos
Mycobacterium leprae (leprosy)
SPECIAL CULTURE TECHNIQUES rabbit testicles
Treponema pallidum (syphilis)
SPECIAL CULTURE TECHNIQUES host cells only
Obligate parasites
STD causing
chlamydia
SPECIAL CULTURE TECHNIQUES hen’s egg
Influenza virus
SPECIAL CULTURE TECHNIQUES Cell culture
Mycoplasma spp
A method of isolating a culture by spreading microorganisms over the surface of
a solid culture medium.
S T R E A K
P L A T E
M E T H O D
A method of inoculating a solid nutrient medium by mixing bacteria in the melted
medium and pour the medium into a Petri dish to solidify.
P O U R
P L A T E
M E T H O D
A plate count method in which inoculum is spread over the surface of a solid
culture medium.
S P R E A D
P L A T E
M E T H O D
