virology Flashcards
composition and structure of a virus
all viruses need host
intracellular
replicate in either nucleus or cytoplasm
either made of
DNA or RNA
single or double stranded
structure made of
capsid- outer part
protein coat- surrounds virus
nucleocapsid
surrounds nucleic acid material
individual protein components
capsomere
-determine whether or not virus will invade a cell
-see if we can produce antibodies against it
shapes
icosahedral- 6 sided 3D
helical- round shape
some contain an envelope which is
extra lipid bilayer that protects virus
naked= no envelope
most virus acquire an envelope from host cell if
they bud out of it
2 ways virus leaves host
budding -does not always destroy a host cell
bursting -most are naked
-destroy host
DNA viruses
herpes
-CMV, EBV, varicella roster
pox
-small pox (bioterrist)
-polio virus
papo?
RNA virus
Orthomyxoviridae - influenza
Togaviridae - Rubella
Rhabdoviridae - Rabies
Rhinovirus- common cold Retrovirus - HIV
viral replication
attachment to host by glycoproteins and to specific receptor
1 in 1000 collisions will result in attachment
specific marker to attach to
tropism
single tropism
only 1 spot
dual tropism
two markers to attach to
X tropism
many sites
penetration
endocytosis
injection- plants do this
fusion
membrane fold around the virus, infuses
once inside can shut down host cell to only make new viruses
uncoating
capsid comes off and exposes genetic material
aka e clips phases, can not detect viral partial during this stage
biosynthesis
replication of virus particles
assembly
reassembly into full viron particles
releases
attach other cells
-release depends on if have envelope or naked virus
Most naked= burst out and destroy
Most envelope= bud out of a cell
now virus in blood stream called
viremia
typically do not increase lactate acid?
specimen collection
when patient is symptomatic - viral shedding at highest
place in viral transport media- enhance survival of virus
what specimen are placed in transport media
Swab/scraping
small tissue
if drys out virus will die
most contain antibiotic to prevent bacterial contamination
common transport media
Ames
stuart
Hank’s
what specimen is not added to transport media
urine
spinal fluid
bronchiolar lavage
will dilute
how to keep transport
2-8 degrees
wet ice
dry ice- will dry specimen
if going to not be run for 5 days can be placed at -70
if collection is a swab either use
dacron
rayon
NO calcium alginate- interfere with viral replication
gold standard for viral detection; complicated and time consuming
cell culture
-even if there is a new test, need to check it out with cell culture
-preparation with cell cultures
primary line
originate from specific organ tissue, and on media only allow a mono layer of cell to grow
-original karyotyping and chromosome number as they originally had
from primary line we subculture cells and place in a new plate
cell passage
primary line can only go through cell passage
a few times before lose ability to have viruses attach to them
secondary cell line
75% of karyotyping as primary and certain viruses only attach to secondary cell line
-most frequently used in culture
-be subcultured 50 times
continuous/ heteroploidy cell line
continuous forever
-start from cancerous line
-simple in needs
-abnormal karyotyping
-serological testing
-Hep2 or HeLa
CPE
cyto pathological effect
-change in what cell looks like
-lyse, change in shape, formation of inclusion bodies, formation of syncytia, change in surface
haeabsorption
adding RBC and absorb onto the surface
shell vial centrifugation
-first used to detect chlamydia and herpes
-coverslip has mono layer of cells, buy the one known to detect specific what your looking for
shell vial centrifugation procedure
-place in nutrient broth
-centrifuge vial: sped up amount of times to infect culture
-incubate 1-5 days
-take cover slip and stain with anti-viral fluorescent monoclonal antibody
-read
EIA
enzyme immuno assay
quick
downside: less sensitive than cell cultures
direct or indirect fluorescence
direct: looking for antigen
indirect: looking for response
PCR
very sensitive and specific
drawback: expensive
but now reimbursement from medicare
cytology
classic example of pap smear and look for CPE
rabies tissue look to confirm
