Card Set Information
Why do we use mircoscopes?
microbes are too small to see with the naked eye
eye peice 10xx
low = 10x
high dry= 40x
immersion = 100x
ocular x objective
example 10x40= 400x high dry
How to use a microscope? (tips for success)
what objective you should start with?
adjust light intensity for clarity
dont turn the light all the way
reduce intensity to moderate
What is a we mount ? And why we use this technique? And Advantages?
wet mount a living suspension of the organism
organisma are alive
see the size and shap
what is hay infusion?
hay infusion is a mixture of lake and and grass or hay. the mixture has O2 pumped into it facilitates the growth of microbes in the lake.
Wet mount Vs smear prep?
see motility, cell arrangement, organism is alive
dead organism but allow to see a specific structure
contain all chemicals compounds necesary to support growth
different organisms have different requirements
Types of media and what each grows?
complex =rich media
for isolation of
tryptic soy agar
brain heart infusion
potato dextose agar
Chemically defined media?
exact chemicals and amount is known
used to isolate specific groups
Living tissue media?
made of living organism
growing host specific pahogen unless live on bacteria
How to calculate amount of media powder given amount of water?
Definition of Sterilization?
the complete destruction of viable organisms in a given environment to prevent contamination.
Type of sterilization?
media and metal objects
Type of sterilization?
type of sterilization?
heat chemicals, antibiotics
gasous- anything that will melt
plastic, petri dishes
What is streak plating and its purpose?
a petri plate containing some type of sterile nutrient agar( tsa,BHI,
purpose to seperate the bacteria in mixed culture so the individual cells can be isolated
when should you flamethe inocluating loop?
Between the streaking of each sector
Labeling a petri dish?
What is a dillution plating and whats its purpose?
a method used to estimate #s of bacteria in a sample
purpose is to
How to perform/calculate several dilutions?
colony forming units
A disease or two caused by old milk?
pour plate method?
second method of obtaining isolated colonies by dilution
Shape/form of colonies?
elevation of colonies?
Margin of colonies?
tetras= groups of four
strep= chains of three or more
facultative- grow without
Aerobic- requires O
is toxic ,requires no oxygen environment to live
is toxic at atmosphere concentrations only small amount
What is Smear Prep?
a procedure used to prepare a bacterial sample for staining in which the bacteria is heat fixed to a slide
What is it used for?
staining and increasing contrast
Disadvantages of smear prep?
motility no longer be studued ditorts the cells apperance
if liquid broth place a loopfull of broth directly on to the slide
if isolated first drop of water on to slide and which a small amount of bacteria is dispersed using a loop
How do you do it?
Why is the gram stain useful?
What are the 4 steps of the gram staining procedure?
what are the difference in the outer protection between gram + and gram -?
What do these cells liik like in the end?
Why is a capsul useful for bacteria?
act as a barrier between the cells
aid the cell in adhering
what is a capsule?
a viscous substance which accumulates and coats the cell and becomes the outermost layer made up of polyssacharides(few Proteins)
What is a capsule Stain?
What is a negative stain?
steaming the background leaving the capsule unstained since it cant be stained.
What is Schaeffer-fulton?
stain capable to distiquish between spores and vegetative cells found primarily in the clostridium and bacillus genera
What is an endospore?
its a dorment form of the bacterium that allows it to servive lean envrionmental conditions./ spores form within the cell( vegetative cell)
What bacterium form endospore?
Why do we steam?
its a primary stain in malachite green is forced into the spore coat.
To distiquish between the spore and the vegetative cell
What is an acid fact bacterium?
stain important for differential for identifying bacteria in the gendo mycobacterium
large amounts of lipids and waxes in their cell wall makes them inpermeable and resistant
alos known as the acid fast stain
allows to identify bacteria with large amounts od lipids and waxes in their cell walls
most commoly in the genus mycobcterium
will appear red-non blue
Why special measures to dye them?
due to that they are impermeable and resistant to many chemicals
What special measures?
what bacteria are acid fast?
What is a selective Media?
has a selection agent or agents added to it prohibits the growth of some organisms
allows the organism of interact to grow while inhibits the growth of others.
What is differential Media?
growth of organisms not inhibited
contains substances that allow different groups grow differently than others when grown on the same media
Mannitol salt agar(MSA)
selects gram + bacteria growth
highest level of salts
mannitol and phenol red
when fermented turn yellow
non mannitol fermenters remain pink
crystal violet bile salts
inhibits growth of gram+
contains lactos and neutral red ph indicator
turn to red colonies
non lactos colonies do not change
Kliglers Iron Agar (KIA)
determinator of varbohydrate fermentation patterns and gas production
determines gram - rod
KIA agar slant
inoculated with a needle( not Loop) stab then streak slant