unit 4 micro Flashcards
a bacterial species is defined as…
a group of cells that share the similar characteristics
a colony is a…
mass of visible cells that arose from a single cell & can be assumed to be genetically equivalent
colony morphology size:
measured in mm
colony morphology shape:
circular, irregular, rhizoid, punctiform
colony morphology margin:
entire, undulate, lobate, filamentous, serrate
colony morphology texture:
shiny/dull & rough/smooth
colony morphology pigmentation:
yellow, beige, white, off-white
colony morphology elevation:
flat, convex, umbonate, raised, pulvinate, crateriform
cell morphology size:
micrometres
cell morphology shape:
cocci, bacilli, vibrio, spirillum, spirochete
cocci is described as:
spherical or round cells
bacilli is described as:
rod-shaped cells
vibrio is described as:
bent rods
spirillum is described as:
spiral-shaped and rigid
spirochete is described as:
spiral-shaped and flexible
arrangement of cocci:
single, diplococci, tetrad, streptococci, staphylococci
arrangement of bacilli:
single, diplobacilli, streptobacilli
cell morphology: the presence of endospores
present or absent
cell morphology: gram-reaction
positive or negative
cell morphology: gram-reaction
positive or negative
gram-negative cells
outer membrane only
gram-positive is
have thicker peptidoglycan layer than negative
what colour does gram-positive stain? gram-negative?
positive: purple
negative: pink
a positive test result indicates:
that the organism is capable of that particular function
a negative test result indicates
that the organism is not capable of that particular function
oxygen tolerance test is
growth in response to oxygen
obligate aerobe:
use of oxygen
die in presence of oxygen
description
yes
no
growth only in areas of high oxygen levels
obligate anaerobe:
use oxygen
die in presence of oxygen
description
no
yes
growth only in the absence of oxygen
facultative anaerobe
use oxygen
die in presence of oxygen
description
yes
no
optimal growth in high levels of oxygen, sporadic growth elsewhere
aerotolerant
use oxygen
die in presence of oxygen
description
no
no
sporadic growth throughout tube
microaerophile
use oxygen
die in presence of oxygen
description
at low levels
at high levels
growth only in areas of low oxygen
fermentation test:
ability to ferment different carbohydrates. each carbohydrate must be tested separately as each microbe is capable of fermenting or not
gelatinase test:
tests the ability to secrete extracellular proteases (ability to digest proteins)
setup for fermentation test:
pH indicator, specific carbohydrate, microorganism
visual results for fermentation:
negative: red, no gas
positive: yellow, no gas & yellow, with gas
can microbe ferment tested carbohydrate
negative: no
positive: no gas - lactic acid fermentation & gas - ethanol fermentation
set up for gelatinase test:
microbe mixed with gelatin
visual results for gelatinase test:
negative: media remains solid
positive: media turns liquid
deaminase test:
presence of deaminase enzymes (ability to digest amino acids)
set up for deaminase test:
pH indicator
microbe
animo acid
visual results for deaminase test
negative: red
positive: magenta
urease test:
testing the ability to digest urea
set up for urease test:
pH indicator
microbe
urea
visual results of urease test:
negative: red
positive: magenta
what are antigens?
molecules that can stimulate the immune system
what are antibodies
protein molecules produced by the immune system that can target and kill antigens
slide agglutination test:
visualized by looking for clumping when an antigen and the corresponding antibody binds
enzyme-linked immunoassay = ELISA
more sensitive and requires less sample than slide agglutination tests
used to detect antigens:
direct ELISA
- patient sample can include: blood, saliva, urine
- used to detect presence of a pathogen, hormone, drugs
step 1 in direct ELISA
add a commercially-prepared primary antibody that will bind to the wanted antigen
step 2 in direct ELISA
after letting the proteins bind, the wells are washed - a block agent in the wash is used to block unbound sites
step 3 in direct ELISA
the patient sample (contains a mixture of antigens) is added
step 4 in direct ELISA
if present, the wanted antigen will bind to the antibody. other antigens are removed through washing
step 5 in direct ELISA
an enzyme-linked secondary antibody is added, which binds to the wanted antigen, if present
step 6 in direct ELISA
after binding, any excess secondary antibody is removed through washing
step 7 in direct ELISA
an enzyme substrate is added, which reacts with the enzyme, if present (horseradish peroxidase) which turns the solution blue after reacting
used to detect antibodies
indirect ELISA
indirect ELISA sample can include? used to detect?
blood serum & detect exposure to a pathogen or vaccine efficacy
step 1 indirect ELISA
add commercially-prepared antigen that will bind to the wanted antibody
step 2 indirect ELISA
after letting the proteins bind, the wells are washed - a block agent in the wash is used to block unbound sites
step 3 indirect ELISA
the patient sample (contains a mixture of antibodies) is added
step 4 indirect ELISA
if present, the wanted antibody will bind to the antigen. other antibodies are removed through washing
step 5 indirect ELISA
an enzyme-linked secondary antigen is added, which binds to the wanted antibody, if present
step 6 indirect ELISA
after binding, any excess secondary antigen is removed through washing
step 7 indirect ELISA
an enzyme substrate is added, which reacts with the enzyme, if present
