Term
| Fundamental characteristics of virus |
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Definition
Obligate parasite
Must be inside cell to rep
Highjacks cell machinery to make new parts
Capsid + genes |
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Term
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Definition
| Infectious agent to transmit viral infection to next cell |
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Term
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Definition
Virus cant synth own parts or E
Much smaller
Less complex
No ribosomes, golgi, etc |
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Term
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Definition
Bilateral w embedded proteins
Derived from cell membranes
Only some viruses |
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Term
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Definition
Protein coat
Protects genome, attachment, entry into cell, enzymes |
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Term
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Definition
Not part of virion
Made during rep process
TFs, polymerases, proteases |
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Term
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Definition
1. DsDNA
2. Ss (+) DNA
3. DsRNA
4. ss (+) RNA
5. Ss (-) RNA
6. Ss (+) RNA w DNA intermediate
7. DsDNA w RNA intermediate
Must be converted into (+) mRNA for transcription |
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Term
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Definition
Flow of info from DNA to proteins
Genome determines flow of info
Info storage (genome)-> info carrier (mRNA)-> proteins |
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Term
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Definition
Illuminate sample w e-
High resolution & magnification
Used for clinical diagnosis, identification, structure (components fit tg, attachment, etc), cytopathic effect |
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Term
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Definition
Visible morphological changes in cells infected w viruses
CPE |
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Term
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Definition
| Used to study disease progression, immune responses, vaccine studies |
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Term
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Definition
Inoculate cells w dilutions of virus & add agar to plate
Plaque = zone of infected dead cells
Used to quantify, titer determines PFU/ml |
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Term
| Quintal assays when virus doesn’t form plaques |
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Definition
Tissue culture infectious dose (TCID) measures CPE
Infectious dose (ID50) for animals
lethal dose (LD50) for animals |
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Term
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Definition
Quantal assay at multiple t’s
Used for virus synth rates |
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Term
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Definition
Isolate nucleocapsid acid & proteins from infected cells
Might use radioactive labels/probes or abs
Used to distinguish viral & cellular components |
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Term
| Genome seq & manipulation |
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Definition
Metagenomics, PCR amplicon, or target enrichment
See what genes are present & what they do
Difficult for viruses bc no common gene or gene type & susceptible host cell line may be unavailable |
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Term
| Multiplicity of infection |
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Definition
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Term
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Definition
| Measure antiviral % inhibition of rep |
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Term
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Definition
| Study of distribution & determinants of health-related states/events in pops & application to control of health probs |
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Term
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Definition
Standard set of criteria for classifying if someone has a particular disease
Clinical criteria (lab tests, symptoms, signs) + limits on t/place/person
Suspected by signs & symptoms -> lab confirmed-> epi linked |
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Term
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Definition
What: health issue
Who: person
Where: place
When: t
Why: how-> causes, risk factors, modes of transmission |
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Term
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Definition
Agent interacts w/ host in envir
Agent: virus biology & genetics
Susceptible host: demographics, SES, culture, bio characteristics
Envir: supports transmission-> physical, bio, social |
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Term
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Definition
| time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent |
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Term
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Definition
| Inoculation period for chronic illness |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| % infected w severe symptoms |
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Term
| General replication cycle |
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Definition
1. Attachment: adherence to plasma mb
2. Entry: cross mb
3. Uncoating: release of nucleic acid from capsid
4. Transcription
5. Translation
6. Rep
7. Assembly: form virus particle
8. Exit: thru mb or lytic |
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Term
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Definition
Adherence to plasma mb
Viral attachment protein + receptor
Specific
Mediated by weak interactions |
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Term
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Definition
Endocytosis (receptor-mediated) or fusion
For some viruses, pH changes in entry endoscopes cause conform changes that cause envelope to fuse w endorse all mb to release virion contents
Some non-enveloped have pore-mediated penetration, inject genes (non-enveloped only) |
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Term
| How receptors are experimentally identified |
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Definition
Abs against receptor block virus binding
Soluble receptor blocks binding/infectivity
Ligand of receptor blocks binding
Adding gene for receptor into resistant cells makes them susceptible |
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Term
| Transcription in all Baltimore types |
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Definition
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Term
| Polymerases/transcriptases involved in viral transcription |
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Definition
DdRp: viral or cellular
RdRp: dsRNA & ss (-) RNA, packaged
RdDp: reverse transcriptase |
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Term
| Translation in eukaryotes |
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Definition
Cap-dep
Sm ribosomal subunit associates w initiation factors & mRNA-> GTP hydrolysis-> lg subunit associates to form EPA regions-> elongation factors allow elongation via tRNA in P region-> signal recognition particle (SRP) allows docking to ER-> termination-> cis Golgi-> trans Golgi |
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Term
| Capping mechanisms for translation |
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Definition
Conventional: cap added by cellular enzyme
Virus specific: cap added by viral enzyme
Cap stealing: take from cellular mRNA |
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Term
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Definition
Internal ribosome entry site
RNA region that recruits ribosome
Folded region |
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Term
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Definition
Viral protein genome-linked
Sm protein on (+) RNA
Recruits ribosome |
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Term
| Replication in all Baltimore types |
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Definition
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Term
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Definition
| Primase, DdRp, RdRp, RdDp, DNA ligase |
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Term
| Location of rep for host vs viral polymerase |
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Definition
Host is always in nucleus
Viral if CP |
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Term
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Definition
1. Form structural units of capsid
2. Capsid assembly
3. Selective packaging of genome & essential genome components
4. Envelope acquisition (some)
5. Release from host cell
6. Maturation (some) |
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Term
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Definition
1. Self-assembly: spontaneously combine, final product is min E st, subunits must collide in correct orientation (high T = more random collisions)
2. Scaffolding proteins: non-structural proteins help assembly
3. Maturation thru cleavage: precursor proteins undergo proteolytic cleavage
Genome can be 1. Initiating factor (components assemble around) or 2. Packaged into procapsid (DsDNA, involves terminate & portal protein)
Side chains of indiv subunits form interactions-> H bonds, disulfide bridges, ionic bonds, etc
Packaging signals distinguish viral vs cell genes |
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Term
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Definition
1. Budding: capsid pushes thru mb, takes belayer w glycoproteins
2. Exocytosis: surrounded by endoscope & released
3. Cell lysis: cell mb bursts to release virus |
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Term
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Definition
1. Vertical: same species, mother to baby
2. Horizontal: same species by human contact
3. Vector-borne or zoonotic: betwn species |
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Term
| Types of horiz transmission |
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Definition
Respiratory: sneezing, coughing, etc
Fecal-oral: GI tract infection, hand washing, contaminated food
Conjunctival: finger to eye, often healthcare settings
Sexual: genital tract
Mechanical: thru skin, touching, needles, cuts |
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Term
| Vector/zoonotic transmission |
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Definition
Reservoir to vector to host
Urban: ppl & vector
Enzootic: animals, ppl, vector
Rural epizootic: farm animals, ppl, vector |
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Term
| Molecular mechs of genetic variation |
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Definition
1. Mutation: polymerases make error every 10^4-10^8 bases
-more likely if shorter gen & rep t, direct horiz transmission, ssRNA
2. Reassortment: coinfection w 2 strains-> segments mixed up in host
3. Recombination: breakage causes fusion of donor seq w acceptor seq
-replication (at polymerase) or non-replication (2 breaks, ligase) |
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Term
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Definition
Shift: genetic shuffling of diff subtypes (recombo/reassert)
Drift: mutations |
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Term
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Definition
Pop structure w lg # of variant genomes (mutant spectra/swarms/clouds)
High mutation rates
Mutants arise continually |
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Term
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Definition
1. Replicative: ability to produce infectious progeny in given envir/host cells
2. Transmission: quantities of viral variants in source & recipient hosts
3. Epi: changes in distribution, prevalence, & composition of genotypes over t to infer relative fitness |
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Term
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Definition
Compare diff in NTP seqs of potentially related viruses
Can measure distance to identify nearest relatives & study evolution
Node = division
Root = assumed common ancestor |
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Term
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Definition
Newly appeared in pop or existed previously & now rapidly inc in incidence or geographic range
Can infect new host, appear in new area, or both |
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Term
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Definition
Virus: mutation & selection, new genes by recombo/reassortment
Host resistance: immunosuppression, nutrition, herd immunity
Transmission: climate, weather, ecosystems, vectors, crowding, air travel, sex, drugs, war, famine, poverty, inequality, job, politics |
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Term
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Definition
Compare diff in NTP seqs of potentially related viruses
Can measure distance to identify nearest relatives & study evolution
Node = division
Root = assumed common ancestor |
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Term
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Definition
Newly appeared in pop or existed previously & now rapidly inc in incidence or geographic range
Can infect new host, appear in new area, or both |
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Term
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Definition
Virus: mutation & selection, new genes by recombo/reassortment
Host resistance: immunosuppression, nutrition, herd immunity
Transmission: climate, weather, ecosystems, vectors, crowding, air travel, sex, drugs, war, famine, poverty, inequality, job, politics |
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Term
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Definition
| Frequency (# cases/# pop) + pattern (t, place, ppl) |
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Term
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Definition
| Causes & factors that influence disease occurrence |
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Term
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Definition
| Diagnosing & community & proposing public health interventions |
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