Exam 1 9/18 Nguyen Micro Flashcards
Purpose of microscopy
initial detection of microbes
Bacterial cell wall charge
negative
Simple stains can be used to stain
bacterial cell walls (non-specific, rapid, negative charge)
India ink (carbon particle) is a type of ___ stain
negative
Quellung reaction
antibody mediated, cause swelling of capsule, allows visualization
capsule inhibits
phagocytosis
Capsule correlates with
virulence
Capsule mediates
adhesion
Which bacteria do not gram stain
spirochetes (too thin)
mycoplasma (no cell wall)
mycobacteria (high lipid content)
Mycoplasma contains ____ in membrane
sterols
You can test for mycoplasma using
DNA, antibodies
Mycolic acid found in
mycobacteria
Mycobacteria is resistant to ____
gram staining (lipid resists stain)
Ziehl Neelsen
AKA acid fast stain
Acid fast stain used for
mycobacteria
What color do acid fast bacteria stain
Red (non/tissues = blue)
Silver stain is used for what organisms
legionella, spirochetes, fungi
types of growth media
liquid (broth) for expanding an organism; semisolid (agar)
Selective media definition
select for specific organism
Differential media definition
distinguish organisms with certain characteristics
Hemolysins
produced by some bacteria. blood breaking
alpha hemolysis
incomplete, partial hemolysis (H2O2 turns agar green)
B hemolysis
complete (streptolysin, exotoxin)
gamma hemolysis
no hemolysis
Macconkey agar is both
selective and differential
What kind of hemolysis do cocci and bacilli do
beta hemolysis
True or false - most microbes can be cultured
false - use molecular diagnosis more often
PCR can make how many copies of a strand of dna
millions
In RT PCR, amplify RNA after its conversion to DNA by:
reverse transcriptase
Serology is study of
serum (antibody in pt serum)
When Ab binds to Ag, the complex can:
precipitate - comes out of solution, can see with naked eye
Radial immunodiffusion
antigen added to wells at dif concentrations, surrounding gel contains antibody, precipitate forms ring around wells
double immunodiffusion can test for:
multiple organisms
Countercurrent electrophoresis
Ag and Ab have opposite charges, they migrate (- side is Ag). electricity speeds up diffusion rate
Latex agglutination
antibodies to specific bacteria coated on latex
Hemagglutination can help with
blood typing
ELISA stands for
enzyme-linked immunosorbant assay
In ELISA, what binds to Ag:Ab?
conjugate enzyme reporter –> glows
Sandwich ELISA can quantify
antigen
Flow cytometry
- immunofluorescence performed on cells count in liquid suspension
- can count type of cells and number
PAM is located: (crispr)
invading virus/plasmid
Cas9
cuts DNA that has PAM
Saliva based testing is a form of
non-invasive biomonitoring
Problems with oral microbial testing
can’t distinguish between variations -
1. different sites on same tooth
2. same site on different teeth
3. different times on same tooth site