LO6

Question 1

acid- fast staining for bacteria that has X in the cell walls

Answer 1

mycolic acids

Question 2

why is it called acid-fast

Answer 2

organisms with mycolic acids resist decolorizing with acid based alcohols

Question 3

notes taken from slide show, manual barely had words in it

Question 4

ziehl- neelsen

acid fast stain

Answer 4

primary stain: carbolfuchsin red
it forms complexes with myolic acids and waxes

heat: softens the walls an allws the dye to go in, use of a hot plate or flame

counterstain: methylene blue or malachite green

Question 5

steps for ziehl- neelsen

Answer 5

primary stain carbolfuchsin red :
acid fast positive and neg are red now

decolorize: HCl, alcohol
positive is still red and neg white

counterstain: methylene blue
positive is red and neg is blue

Question 6

kinyoun stain

Answer 6

more commonly used modified ziehl- neelsen

utilizes increased: phenol and basic fuchsin concentrations

cold method

Question 7

trouble shoot

no acid fast

false + acid fast

Answer 7

smear too thin
background too dark
old stock
no heat

contamination
artifact that is +

Question 8

darkfield microscopy

Answer 8

-oblique illumination
- diffraction of light
-specimen is bright and backg is dark
-high contrast
-little cellular details
-used when : staining would harm, specimen is too small

Question 9

fluorescence microscopy

fluorescence

Answer 9

-fluorecnce is energy, that is emited as light, when electrons return to ground state after excitation

Question 10

fluorochroming

Answer 10

-the fluorescnce dye has a direct interction w/ bacterial cell wall

-dye enhances how well we see

-need 10^4 organims/mL

-color dpeends on dye and excitation wavelenghts

Question 11

fluorescent stians

acridine orange

Answer 11

-bind nucleic acids

-confirms bacteria on blood culture

-dye- orange

-stains also Mycoplasma spp

Question 12

fluoro stain

auramine-rhodamine

Answer 12

-affinity to mycolic acids

-looks yellow or orange
-background green from counterstain

-can detect small numbers

-must be confirmed with ZN or Kinyoun

Question 13

fluoro stain

calcofluor white

Answer 13

-binds to chitin in the walls of fungi

-used for detection of fungus or to view its features

-stain blue white or green
-background dakr

-may be mized with KOH to dissolve keratin

Question 14

Immunofluorescence

Answer 14

-Ab to organims bound to dye

-amplifies dyes once bound to Ag

-increased specificity
-used as direct stain for slow growing bacteria

bacteria can be green, blue

Question 15

negative stain

India Ink

Answer 15

-for organisms that cannot be heat fixed

-neg: the bacteria is pale and the background is colored