Exercise 7_ Bacterial Capsule Flashcards
mainly composed of polysaccharides but may contain polyalcohol and polyamines
capsules
capsules are composed of (3)
polysaccharides polyalcohol polyamines
location of capsule in gram positive bacteria
external to the cell wall
bacteria with capsule that is external to the cell wall
gram positive bacteri
location of capsule in gram negative bacteria
external to the outer membrane
bacteria with capsule that is external to the outer membrane
gram negative bacteria
this refers to when the material is tightly bound and remains attached to the cells and there is a defined shape
capsule
this refers to when the material is loosely bound and there is no distinct boundary
slime layer or glycocalyx
slime layer is also known as
glycocalyx
glycocalyx is also known a
slime layer
functions of capsules
- allow the cells adherence to surfaces - protects cells from desiccation, chemical and physical inhibitory factors - contribute to biofilm formation - can boost bacteria’s virulence (protecting them from the host’s immune system) - confer to the cells antigenic determinants leading to variation in pathogenicity - resist phagocytosis - exclusion of bacterial viruses and hydrophobic toxic materials
what were developed based on bacterial antigenicity
some vaccines
some vaccines were developed based on the ____ ___ of a bacteria
capsule antigenicity
aids that can help visualize the capsule/slime layers
- electron microscopy - phase contrast microscopy - various staining techniques - special media
3 staining methods employed in this exercise
- Duguid’s method/negative staining - anthony’s method - maneval’s staining method
_____ ____ with the use of ink will provide a colored background as the large particles of ink will neither penetrate the tight layers of the capsule nor stain the bacterium
negative staining
negative staining will only stain the _____ of the cells as the large particles of the ink will neither penetrate the tight layers of the capsule nor stain the bacterium
background
charge of basic dye
positive
basic dye interacts with the ____ ions of the bacterial cell wal
negative
it interacts with the negative ions of bacterial cell
basic dye
charge of acidic stain
negative
acidic stain is used to color which part of the specimen>?.
background
basic stain is used to color which part of the specimen>?.
cells
indication of capsulated cells after staining
clear halo b/w the colored background and the stained cell
what does the clear halo b/w the colored background and the stained cell indicates
presence of capsule
examples of mordants
metal ions alcohol acetic acid
function of mordant
precipitate the capsular material to make it visible
this aid in the precipitation of capsular material for better visualization
mordant
control organisms used for this exercise
B polymyxa
culture media utilized for this exercise
Nutrient agar w/ 2% glucose Nutrient agar w/ 2% sucrose
percent concentration of the glucose and sucrose added to NA
0.02
mounting medium of negative staining/duguid’s method
india ink/nigrosin
this method utilizes india ink/nigrosin as mounting medium
negative staining/duguid’s method
can mounts for capsular observation be heat fixed?
NO
Mounting medium of anthony’s method
6% glucose soln
this method uses 6% glucose soln as a mounting medium
anthony’s method
percent concentration of the glucose solution for anthony’s method
0.06
primary stain of anthony’s method
crystal violet
time requirement in using crystal violet as a primary staining agent in anthony’s method
2 min
instead of water, this is used to wash crystal violet in anthony’s method
copper sulfate
in duguids method/negative staining the capsules will appear as ____ ____
clear zones
this method results to capsules being seen as clear zones, with refractile cells and brownish-black background
negative staining/duguids method
in duguid’s method/negative staining the cells will appear as
refractile cells
in duguid’s method/negative staining the background will appear as
brownish black
this method results to capsules being seen as light blue to colorless, with blue/dark purple cells
anthony’s method
in anthony’s method the capsules will appear as
light blue to colorless
in anthony’s method the cell will appear as
blue/dark purple
mounting medium of maneval’s staining method
congo red
which method uses congo red as a mounting medium
maneval’s staining method
after emulsifying the samples in congo red, the next staining agent is
maneval’s stain
time requirement in using maneval’s stain in anthony’s method maneval’s staining method
5-10 mins
bakit naglalagay ng tissue sa ibabaw ng smear preps before maglagay ng staining agents
para walang debris na matransfer dun sa sample
amount of india ink/nigrosin that is mounted in the glass slide
loopful
amount of 6% glucose solution that is mounted in the glass slide
loopfu
amount of congo red that is mounted in the glass slide
a drop
what do we use to rinse the maneval’s stain
water
in anthony’s method, this component helps prevent the capsule shrinkage
glucose solution
pH indicator component of maneval’s staining metho
congo red
at or below pH 3.0 congo red turns to
blue
at what pH congo red turns to blue
pH 3.0
above pH 5.2 congo red turns to
red
at what pH congo red turns to red
above pH 5.2
the component of maneval’s staining method that increases the penetration of the stain
phenol
the component of maneval’s staining method that acts as a chemical fixativ
FeCl3
the component of maneval’s staining method that penetrates the exopolysaccharide layer of the cell
acid fuchsin
the component of maneval’s staining method that changes the background from red to blue
acetic acid
why are smears for capsule staining not fixed by heat?
- highly hydrated molecule, can be diminished, desiccated, distorted, or destroyed by heating - can alter the overall morphology of the bacterial cells - produce a clear area around the cell that can mistakenly be identifies as a capsul
condition/s where the capsule is formed
- response to nutrient limitation or stress conditions
