NEGATIVE STAINING LAB Flashcards
t/f heat fixation is required for negative staining
false.
negative staining requires the use of ___ stain
acidic /negative
examples of negative stains
India ink or nigrosin (negative stain stains background of bacterial cells)
benefit of not heat fixing (2)
cells are not subjected to teh distoring effects of hcmicals and heat, natural size and shape are seen.
also able to see bacteria that are difficult to stain like some spirilla
t/f although negative staining doesnt heat fix, bacteria are still killed
false - they are not killed and handle slides with care
Whats the shape of Bacillius Megaterium
a very large rod
gram status of Bacillius megaterium
gram +
what is the arrangment of bacillus megaterium?
streptobaccili (chain)
the main application of negative staining?
to see if the organism has a capsule
_____ an important infectious agent found in bird dropping that is linked to meningeal and lung infections in humans
Cryptococcus neoformans
what technique is often used in identification of fungi such as Cryptococcus neoformans
negative staining (see if it has a capsule)
prodecure for negative stain
- place a small drop of acid stain (india ink, nigrosin, congo red) close to one end of a clean slide.
- using aspectic technique place loopful of incoculum from M. luteus to dro pof dye and mix (DONT SPREAD like in simple smear)
- place a nother slide agains drop at angle and spread along slide
- spread away from drop (PUT IN BIOHAZARD BIN)
- air dry DO NOT HEAT
does stain or organism go first in acid stain
add stain to slide
in what stain technique do you rinse with alchohol
gram stain (after iodine treatment)
in both simple and negative stain always spread sample to size of a dime
FALSE - only in simple smear
