Microbio Lec 5
Terms
undefined, object
copy deck
-
Lec 5
- Law of growth -
- dN/dt=kN
N = population
t = time
k = specific growth rate con. -
Lec 5
- characteristics of K
in the law of growth -
expermintal calc
- k=2.303(log N-log No)/t
if any parameter changes,
- k must be recalculated -
Lec 5
- Methods to measure
microbial growth
(name them) -
- turbidity (light scatter)
- counting chamber
- electronic particle counter
- FACS (fluorescent act. cell sort)
- Dilute and plate -
Lec 5
- Counting Chamber
characteristics -
- Used to get population (N)
- works like hemocytometer
- pros
- counts differentially
(by shape or stain)
- immediate answers
- easy and somewhat quick
- cons
- need 100x microscope
- counts both dead & live -
Lec 5
- Electronic Counting chamber
characteristics -
- uses change in conductivity to
measure (N)
- utilized after getting N by
other count method
- utilizes electrodes and a
conductive solution
- Pros
- once you have N, you dont
need to count
- a drop in current equals
presence of microbes -
Lec 5
- Turbidity and Optical
Densities (O.D.)
characteristics -
- spectrophotometer is used to
measure O.D.
- Light in minus light out = OD
- measures amount of light
scattering (cloudiness)
- Pros
- easy and quick
- cons
- requires spectrophotometer
- cant distinguish between
dead & live -
Lec 5
- Dilute and Plate
characteristics -
- used to verify other other
methods of microbe growth
- pros
- counts only live members
- used for anti-bio type
exp to measure viablity
- cons
- takes 24-48 hrs -
Lec 5
- Dilute and Plate
- Why is this method used
for anti-biotic trials? -
- can distinguish between
1 - slow growth or actual
killing
2 - really dead vs. stunned -
Lec 5
- Growth Curve
- purpose -
- measures pop vs. time over
some interval
- has 4 phases
- normally shows 2 results
1 - turbidity (light
scatter)
2 - Dilute and plate -
Lec 5
- Growth Curve
- Lag Phase -
- 1st phase
- Time before growth of
organisms
- may or may not be seen in lab -
Lec 5
- Growth Curve
- Exponential Phase -
- Law of Growth is used and
calculated for this phase
- proper calc of (k)are made
- population # increases -
Lec 5
- Growth Curve
- Stationary Phase -
- No growth takes place
- food is used up
- _____ exaggerates pop b/c it
counts dead pop as well -
Lec 5
- Growth Curve
- Death Phase -
- Population declines as
organisms die (no shit) -
Lec 5
- Types of growth media
- What is a media -
- Substance with which you grow
microbes/organisms -
Lec 5
- Types of growth media
- Name them -
- Defined Media
- Undefined Media
- Minimal Media
- Selective Media
- Differential Media -
Lec 5
- Types of growth media
- Defined Media -
- Media in which you can write
the chemical form. for all
ingredients -
Lec 5
- Types of growth media
- Undefined Media -
- Media in which 1 or more
ingredients you cannot
write a chem. formula -
Lec 5
- Types of growth media
- Minimal Media -
- Media in which the minimal
amount of chemicals is used
for microbes to grow -
Lec 5
- Types of growth media
- Selective Media -
- Media in which chemicals are
used to allow certain microbes
to grow while denying growth
for others (selection) -
Lec 5
- Types of growth media
- Differential Media -
- Media in which multiple
microbes can grow, but are
differentiable by
phenotype -
Lec 5
- Classification by Physical
Parameters
- List the parameters -
- Temperature
- Hydrostatic Pressure
- Osmotic Strength
- pH -
Lec 5
- Classification by Physical
Parameters
- Temperature
- characteristics -
- Utilizes Arrhenius Plot for
growth curve analysis
- Greater the (k)= higher growth
rate
- (k)max = summit of curve -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Psychrophiles -
- Love Cold
- Ideal K = 4 C or refridge temp
- Can grow in cold b/c lots of
PUFA (polyunsat fatty acids)
- keeps membranes fluid at
cooler temps -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Psychrophiles
- facultative -
- Can grow in the cold, but
would rather have warm
- optimal growth >20 C
- AKA Psychrotrophs -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Psychrophiles
- Obligate -
- Must grow in cold temps
- optimal growth <20 C -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Mesophiles -
- Middle temp, like inside body
- Ideal K = 37 C -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Thermophiles -
- Hot loving
- Ideal K = 60 -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Hyperthermophiles -
- exteme heat loving
- Ideal K = 88 (106???) -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Thermophiles
- Importance of
thermophiles -
- Enzymes very important for
microbio industry
- Provides Taq DNA Polymerase
for PCR reactions
- it increase amount of DNA -
Lec 5
- Classification by Physical
Parameters
- Temperature
- Thermophiles
- How did they
survive? -
- Developed 1st in Evolution
- Utilizes Amino Acids with more
Ionic bonds (stronger DNA)
- Membranes has C40 lipids
- single layer membrane
- high in sat fatty acids
- DNA is positive super coiled -
Lec 5
- Classification by Physical
Parameters
- Hydrostatic Pressure
- Barophiles -
- Love/need high pressure
- high Hydrostatic Pressure
(Deep Sea)
- Cell membrane is 100%
permeable to H2O
- pres. inside= pres.
outside -
Lec 5
- Classification by Physical
Parameters
- Osmotic Pressure
- characteristics -
- microbes that can grow in
varying concentrations of Salt -
Lec 5
- Classification by Physical
Parameters
- Osmotic Pressure
- Osmotolerant - - microbe that can grow in wide degrees of osmotic pressure (salt content)
-
Lec 5
- Classification by Physical
Parameters
- Osmotic Pressure
- Halophiles - - microbes that require high salt content to grow
-
Lec 5
- Classification by Physical
Parameters
- pH
- Characteristics -
- microbes that grow at varying
degrees of pH -
Lec 5
- Classification by Physical
Parameters
- pH
- Acidophile - - pH = 0 to 5.5
-
Lec 5
- Classification by Physical
Parameters
- pH
- Neutrophile - - pH = 5.5 to 8.0
-
Lec 5
- Classification by Physical
Parameters
- pH
- Alkalophile - - pH = 8.5 to 11.5