virology 3 Flashcards

DNA
Terms Definitions
Hepadnavirus
HBV
Deltavirus
HDV
m.o.i.
pfu/cells
Reovirus members
Rotavirus
HDV family
delta
pseudoappendicitis
Yersinia enterocolitica
DNA viruses
HHAPPPPyHepadnaHerpesAdenoPoxParvoPapillomaPolyoma
what causes bronchiolitis
RSV
what is SARS
coronavirus
adenovirus transmission
fecal oral
rubella diagnosis?
usually clinically
what family: Measles
paramyxo
Culex mosquito
SLE, WNV.
Coxsackievirus
herpangina (oral blisters)myocarditis
what causes common cold
rhinoviruscoronavirus
what is AZT?
dT analog
Hepadna viridae viruses:
Hepatitis B
Measles
Cough, coryza, conjunctivits, photophobia, Koplik spots, maculopapular rash from face down. Complication: SSPE
What are the Orthomyxoviruses?
Influenza
Flavivirus
HCVYellow feverDengueSt. Louis encephalitisWest Nile
how is HEV spread?
fecal oral
is htere progressionto hepatocellular carcinoma in HAV?
no
Calici viridae viruses:
Norwalk, Hepatitis E
Dengue
Fever, myalgia, arthralgia, petechiae, thrombocytopenia, neutropenia.
Polyomavirus
JC - progressive multifocal leukoencephalopathy
# of segments in Orthomyxovirus
8
only single stranded DNA virus
Parvoviruspart-of-a-virus
does HAV replication overstress the hepatocyte?
on
WHat do you use ganciclovir on?
CMV
Two kidney transplant recipients developed symptomatic anemia requiring blood transfusions. Common causes of anemia, such as gastrointestinal bleeding, iron vitamin deficiencies, hemolysis, and drug toxicities, were ruled out. A peripheral smear revealed
Parvovirus B19
DNA viridae:
Herpes, Hepadna, Adeno, Papova, Parvo, Pox (HHAPPPY)
Characteristics of Caliciviruses
Non-enveloped, +ssRNA, linear, icosahedral
Yellow fever virus symptoms
high feverblack vomitjaundiceCouncilman bodies (acidophilic inclusions) in liver
steps of infection
adsorption, penetration, uncoats (capsid removed), component production, component assembly, release
DNA viruses recombination
homologous recombination through cellular based enzymes are virally encoded enzymes
Prevention of HBV
1) vaccination (HBs antigen subunit)2) passive immunization: neonates of carrier given immune globulin along with vaccination course
Bunya faamily members
hemorrhagiv fever + renalHantaan pulmonary syndrome
describe bronchiolitis
acute inflammation and necrosis of respiratory epithelium in the bronchiolesacute onset of wheezing and hyperaeration, tahcypneamainly due to RSV
What is the target of Zanamivir (Relenza), the newly approved drug for influenza virus infection
Neuraminidase
Viruses that can be immediately translated into protein:
(+) stranded
Toga viridae viruses:
Mosquito borne encephalitis (WEE, EEE, VEE), Rubella
Characteristics of adenovirus
Naked, dsDNA, linear, icosahedral, replicates in nucleus
Malignancies by EBV
Burkitt's lymphoma: t(8:14) mandible or abdomen; Hodgkin lymphoma; Nasopharyngeal CA.
Pathogenesis of EBV
Infects nasopharynx, salivary and lymphoid tissue --> latent infection in B cells via CD21 receptor --> production of atypical T lymphocytes with heterophile antibodies
longitudinal
of or pertaining to longitude or length:
adsorption
virion attaches to cell via specific reaction between receptors and virion attachment protein (shape)
helical symmetry
cylinder shape TMV (naked) VSV (enveloped
cubic symmetry
spherial shape polio and adenovirus (naked) herpes (enveloped) nucleocapsid is inside of envelope
2'5'oligo A synthetase
Interferon makes the inactivate synthetase which becomes activated upon contact with dsRNA, which causes ATP to become pppA(2'p5'A)n (n= 3-10) oligo which as 2-5 linkage instead of 3-5 linkage, which activates RNaseL which is there all the time but inacti
T=4
subdivide face into 4 triangles, place pentamers at each regular vertex = 12, then add a hexamer at each new vertex = (3x20=60 /2 (since each share one) so 30 hexamers) 12x5 = 60 30x6 = 180 180+60 = 240 total protomers.
potential complications of measles
1) encephalomyelitis2) giant cell (primary) pneumonia in immunocompromised3) secondary bacterial pneumonia4) keratoconjunctivitis5) SSPE: subacute sclerosing panencephalitis. rare, 7-10 years later
clinical features of cosxackie?
multiple serotypescause tons of diseasesherpangia-fever, st, acute onset (A)and, foot, mout (A)aseptic meningitis (A)epidemic conjunctivitis (A)pleurodynia (chest pain and fecer) (B)myocarditis/pericarditis (B)neonatal infection (B)
What is the leading cause of chronic hepatitis/cirrhosis and liver x-plant requests?
HCV
what are WIN compounds:
capsid binding antiviray agentsbind to a canyon on rhino surface and prevent binding and entrynot effective agains non-rhino coldsdifficult to administer
What does type 1 interferon do
Inhibits mRNA translation
What would be the treatment for an HIV infected individual with CMV retinitis
Ganciclovir
Orthomyxo viridae virus properties:
RNA, Helical, Enveloped, ss segmented, (-) stranded
Calici viridae virus properties:
RNA, Icosahedral, Naked, SS nonsegmented, (+) stranded
Steps of viral reproduction:
Absorption & penetration, Uncoating, Synthesis of viral protein, Release of virions
Life cycle of AIDS virus
gp120 binds CD4/CCR5/CXCR4; endocytosis into cell looses envelope; dsDNA is synthesized by reverse transcriptase in cytoplasm; the DNA and integrase move into nucleous and incorporated into host genome forming provirus; transcription and translation; virus assembly and release taking host cell membrane and viral glycoproteins
What are the live vaccines?
Mumps, Rubella, Varicella-Zoster, Measles, Adenovirus, Polio (Sabin), Small Pox, Yellow Fever. "Mr. V.Z. Mapsy"
HBV polymerase
RNA pol: reverse transcribes RNA from DNADNA dep DNA pol: transcribes DNA from RNA template
divided genomes RNA
segmented RNA (dsRNA 10 reovirus, ssRNA 8 flu A), individual pieces are encapsulated in a single particle, some have their segments in different particles alfalfa mosaic virus tripartite, cowpea virus bipartite for infection all particles need to be prese
DNA polymerases
require a primer usually RNA, large virus genomes ode for their own poly
naked capsid
lack an envelope just protein coat around genomic data
binal symmetry
have both cubic and helical symmetry T4 head tail spaceship
rolling circle replication
phiX174, T4, lambda, site specific nuclease that nicks the outer circle in a dsDNA, the 3' end is extended, with the inner template rolls to produce new strand and the other side is also replicated causing dsDNA concatemers
tropism of poliovirus
only humans some non-human primate cells, only a subset of human cells intestinal mucosa, lymphoid tiisues some neuronal does not infect mice
What are WIN compounds?
Anti Rhinovurs agents (common common cold virus)80% of rhinoviruses use same receptor (ICAM-1) for docking and enntry.WIN compounds were designed to fit in the putative receptor binding domain.They prevent Rhinovirus entry
What makes up a virion?
NAproteinssometimes a lipid envelope w/glycoproteins
How do you treat HAV?
No drugsCan give pooled immunoglobulin, although it is notbecoming low in titers of anti-HAV
name barriers to viral entry via respiratory tract
mucusciliated epitheliumsecretory IgAlymphocytes, neutrophils, alveolar macrophages
is 5 end of viral RNA of HAV capped?
no
In what virus is viremia an important event in the pathogenesis
Measles virus
AIDS env gene
Encodes gp160 which is cleaved to gp120 (binds CD4, CCR5, CXCR4) and gp41 (viral fusion)
only DNA virus that isn't isohedrical
Pox in a box
End problem
where RNA primer is left on lagging side
Virus against interferon 2
Influenza NS-1, blocks binding of RIG-1 to dsRNA
Characteristics of antiviral state
Mx protein induced (GTPase that inhibits the transcription of - strands like flu) 2'5'oligo A synthetase induced. RNA activated protein kinase (PKR) is induced
gene expression for +-ambisense RNA viruses for euks
Bunyaviruses (hantavirus) arenaviruses (lymphocytic choriomeningitis virus LCM) segmented genome(x2) = 5' end has gene 1 is + sense then gene 2 is - sense then 3' end with a hairpin between the two senses early transcription by virion transriptase transc
virus against interferon 4
Herpes Simplex synthesizes analogs to oligo A that block activation of RNaseL
RNA viruses recombination 1
Segmented genomes can be reassorted infect same cell the cell can't remember which segments are from where so encapsids randomnly. equals recombinant virus, can be with pig//bird virus that can have increased pathogenicity antigenic shift
Virus against interferon 1
Vaccinia EL3 protein, HSV US11 protein, and reovirus sigma 3 bind dsRNA
Disease course of measles
1) breathe in droplets2) 10-14 days asymp incubation3) then high fever4) cough, head cold, conjunctivitis5) characteristic rash on head and neck6) Koplik's spots on buccal mucosa
What characteristics do envoloped viruses have?
1) need envelope to survive2) sensitive to lipid solvents (chloroform, ether, detergents, bile_3) few are stable in GI tract (bile) and transmitted fecal-oral4) istable in dry/nonaqueous environment
Does polio evade host response?
No. "hit and run" infection strategy
what is foscarnet? what used for?
Pyrophosphate analogused for HSV, CMV, HIV
what is adefor? what used for?
nucleoside MMONOPHOSPHATE analog (of dAMP)used for HIV and HBV
Severe Shock Syndrome after re-infection is caused by a virus that belongs to what family
Flaviruses. Dengue and Hepatitis C are flavorful viruses
Characteristics of DNA viruses
All dsDNA (except parvo); All linear (except papova, hepadna); Icosahedral (except pox); Replicate in the nucleus (except pox); All naked (except herpes, hepadna, pox)
mutation rates viral RNA replicases
no proofreading, no mismatch repair, 4x10^-4 10^-4
poxvirus continuous ends
dsDNA large, there are no free ends not exactly a circle but the ends are a circle endonuclease cleaves at these ends one on each side causes an inverted repeat then continues as parvovirus replication
Mutation Rates cellular replication machinery
before proofreading 10^-4 10^-5 with proofreading 10^-6 10^-8 with mismatch repair 10^-9 10^-10
Subunit theory coding limitation
viruses do not have coding capacity for one large protein to form entire coat must then use repeating subunits
What causes most damage in HBV?
CTL response, directed probably at HBc or HBe antigens
why are nonspecitific immune responses important early in viral infection?
bc immune responses are slow:IgM: 3-4 days post infIgG, IgA: 7-14 days post inf
What would be the treatment for a 30 year old woman with chronic hepatitis C infection
Interferon plus ribavirin
Viral genetics: phenotypic masking
Two virus infect a cell. The surface proteins of one virus (A) coat the genome of the other (B). The surface proteins of A determine infectivity while the viral progeny will have the genome of B.
RNA activated protein kinase (PKR)
Is 5-fold induced by interferon its inactive state, dsRNA (long enough to have two on one) and ATP activate it trans phosphorlyates, which induces active eIF-2alpha to become phosphorlyated by ATP which inactivates which prevents initiation of translation
crystallographer's argument for subunit
only way to get regular symmetry out of irregular subunits is to aggregate the subunits
prokaryotic mRNA vs eukaryotic mRNA
proks mRNA is polycistonic with AUG rbs shine dalgarno sequence (30S then 50S) euks are monocistronic have 5'cap that binds 40S scans for first AUG then 60S binds translate also has poly A tail leaky scanning can bypass first AUG
2 classifications of hepatitis
Acute: symptoms less htan 6 mo; a few are fulminant w/poor prognosisChroinic: Symptoms >6 mo
What kind of viruses are Interferons most useful for? examples?
Best for RNA virusesUses: HCV, papillomaCan theoretically be used prophylactically for: Rhinovirus, RSV, coronavirus, influenza
You are stationed in Japan. A 3112-month-old male presents in August with a history ofdiarrhea and fever. On physical examination, he is irritable and has tachycardia with a pulseof 180 beatslmin. Vesicular lesions are observed on his mouth,
D contains a single-stranded RNA genome that is infectious
What is positive sense RNA?
Viral RNA that can be used as mRNA
Viral solutions to end problem
1.replicate as circle so no ends some linear genomes form cohesive ends like lambda to form a circle also T4 but by intramolecular recombination 2.Form concatemers = tandem repeats of genome (T7) where both ends are the same they get replicated have e
how do latent herpes infections avoid immune system?
infected neurons do not express and display HLA-I
do most viruses replicate in human RBC's?
no, but RBC's often nevertheless have virus receptors. utilized in hemagglutination and hemadsorption tests.
What is pathology of HCV due to?
Both cytotoxic T cells AND virus induced cell death (unlike HBV, which causes no direcy cytopathology)
What is an important and immediated concern to the hospital staff with a newborn that has been diagnosed with congenital rubella syndrome
The high probability that the child is excreting infectious virus
What is AIDS defined by
CD+4 T cell count is less than 200 per mm3 and opportunistic infections are present
gene expression for dsRNA viruses for euks
Reoviruses (10) and phi6 (3) have segmented dsRNA genomes, the virion transcriptase makes monocistronic +mRNA from these segments which can then be translated. reo has caps makes its own both reo and phi6 have no poly A tail Reovirus has conservative repl
What is the deal with adenovirus and portal of entry?
Normally a minor cause of respiratory infectionMore serious where large number of persons are housed together (boarding schools, military camps)WT portal of entry: URT and oropharynxVacccine: released in GI, where it develops into nonpathogenic infection and gives excellent immunity to respiratory adenovirus
gene expression for DNA viruses for euks
need a promoter for each gene in order to get monocistronic mRNA (poxviruses only uses this scheme) or undergoes mRNA splicing where two genes are transcribed on same mRNA with a 5'CAP and mRNA for gene 1 has extra info, but splice to remove gene 1 so mRN
Once you have ds DNA, where do the stages of RTase pathway occur?
1) ds DNA --> mRNA : nucleus (via host RNA pol II)2) mRNA --> ds DNA : cytoplasm (RTase and RNase H)
Parvovirus
B19
Rhabdoviruses
Rabies
coxcackivirus family
picorna
RSV family
paramyxo
HCV family
flavivirus
Mumps
parotitisorchitisaspetic meningitssterility after puberty
Adenovirus
febrile pharyngitispneumoniaconjunctivitis - pink eye
Poxvirus
smallpoxvacciniamolluscum contagiosum
Hepadna family members
HBV
Filo family members
EbolaMArburg
Retro family members
HIVHTLV
What causes laryngotracheobronchitis
paraflu
Hep C family
flavivirus
Bunyaviruses
California encephalitisSandfly/Rift Valley FeversCrimean Congo hemorrhagic feverHantavirus
HIV p24
capsid protein
Rabies virus
Negri bodies
how many measles serotypes?
1
Flavivirus members
Hep CSLEJETBEWNVDengueYellow fever
MCC of infantile gastroenteritis
Rotavirus
AIDS tat gene
Upregulates transcription
killed vaccines
RIP AlwaysRabiesInfluenzaSalK PolioHAV
Are most polio infections symptomatic?
NO
correction
viral RNA, not viral DNA
Where are smallpox inclusion bodies?
cytoplasm
Nonenveloped RNA viruses:
Picorna, Calici, Reoviridae
What are the Reoviruses?
Reovirus, Rotavirus
HIV gp41 and gp120
envelope proteins
asymptomatic
showing no evidence of disease.
Are progeny viruses produced by latently infected cells
never
Herpes family members
HSVVZVLMVEBVHHV 6/7HHV 8Monkey B
What accomanies (serologically) resolution of persistant HBV infection?
anti HBs antibodies
A 42-yr-old Haitian-American woman was diagnosed with T-cell leukemia. According to her sister, their deceased mother breast-fed all the children. The sister of the patient also reported that their mother had suffered from progressive difficulty walking
A, CD4-positive
Nuclear replicating RNA viruses:
Retro and Orthomyxo
Polio
Destroys anterior horn motor neurons. Flaccid paralysis without sensory loss. Live vaccine (Sabin), killed vaccine (Salk)
Infectious hepatitis
HAV. Fever, malaise, headache, vomiting, coluria, jaundice.
Non-enveloped viruses
Naked CPR and PAPP smearCalicivirusPicornavirusReovirusParvovirusAdenovirusPapillomaPolyoma
protein primers
adenovirus, poliovirus, linear dsDNA, has terminal protein on 5' ends covalent bond, the terminal protein is a vestige, C nucleotide on DNA, which is attached to a serine by a phosphodiester bond, polymerase attaches to terminal protein which causes the b
Quasispecies
where bacterial genome are relatively static whereas RNA viruses are a mixture of diverse genetic variants due to their being close to an error with every replication
Picorna family tree
Subsets:1) rhino2) entero3) Hepato (hep A)Entero members:1) coxsackie2) echo3) polio4) entero
3 generalforms of nucleocapsid morphology/symmetry
1) helical/rod2) icosahedral/spherical3) complex
Is there a lifelong immunity for HAV?
no
CD4+ T cell depletion is associated with what virus
HIV-1
The current poliovirus vaccine recommended for healthy children in the US is what type of vaccine
Killed virus vaccine
A 17-year-old high school girl presents to your office with cervical lymphadenopathy, a sore throat, and fever. On her peripheral blood smear, you notice an atypical lymphocytosis.Physical examination of her abdomen shows an enlarged spleen. The vi
Nasopharyngeal carcinoma
RNA viridae:
Toga, Corona, Retro, Picorna, Calici, Reo, Orthomyxo, Paramyxo, Rhabdo, Bunya, Arena, Filo
Shingles
VZV. Pain and vesicles restricted to one dermatome in the 5th or 6th decade. Reactivation of latent infection.
Kaposi sarcoma
Malignancy of epithelial cells caused by HHV-8 which has a gene that turns on VEGF. Seen in AIDS.
post transfusion and IV drug user's hepatitis
HCV
RNA replication nomenclature
replication = replicase (RNA polymerase), reverse transcriptase (retroviruses) transcription = transriptase sometimes they are the same
Infectivity Ratio
number of infectious particles / number of particles
Von Magnus phenomenon
titer of infectious particles decreases with each passage, titer of defective particles increases with each passage. Start with a plaque, make 1st viral stock to cells (titer and total particles), take 1st with a high m.o.i to 2nd on, and on, particles st
What can infect the conjunctiva? is it localized or systemic?
adenovirusesherpesvirusesusually remains localized, but can be a secondary result of systemic infection started elsewhere
How do interferons work?
Cytokines induced in infected cellscan induce antiviral and immmunomudulatory responsescan be induced by administering ds RNASome downstream IF effects can block RNA and protein synthesis, thus stopping those infection steps
What is the MOI?
multiplicity of infectionNumber of infectious virions per cell, at the outset of infection process in a ell culture.
which 2 virus families use RT path?
RetroHepadna (HBV)
Cytopathic effect (CPE) is easily measured in tissue culture in all of the following virusesEXCEPT(A) enterovirus 7 1.(B) herpes simplex vin~tsy pe 2.(C) HIV-1.(D) respiratory syncytial virus.(E) rubella virus.AN
E, rubella virus
Live attenuated virus vaccines are used for all of the following viral diseases EXCEPT(A) chickenpox.(B) hepatitis B.(C) measles.(D) mumps.(E) rubella.ANS:
B, hepatitis B.
What is the number one military mission-aborting viral disease
Dengue virus
Paramyxo viridae virus properties:
RNA, Helical, Enveloped, ss nonsegmented, (-) stranded
Reo viridae virus properties:
RNA, Icosahedral, Naked, dS segmented
Picorna viridae viruses:
Polio, Coxsackie, ECHO, Hepatitis A, Rhino, New Enteroviruses
Herpes viridae viruses:
Herpes simplex 1 & 2, Varicella-zoster, Cytomegalovirus, Epstein-Barr, Roseola (Herpes 6)
Parvo viridae virus properties:
DNA, Icosahedral, Naked, ss linear
Viral genetics: recombination
Exchange of genes between 2 chromosomes
Diseases caused by Norwalk virus
Acute gastroenteritis. Watery diarrhea, nausea, vomiting. Associated to outbreak in cruise ships.
Pathogenesis of VZV
Respiratory tract --> local lymph node --> primary viremia --> spleen and liver --> secondary viremia --> skin rash --> latency in dorsal root ganglia --> reactivation due to stress causes vesicular lesions and severe nerve pain
viremia
the presence of a virus in the blood.
T=?
12 pentamers, total capsomers = 10T + 2, total protomers = 60T
RNA viruses recombination 2
Intact genomes- copy choice recombination a poliovirus has two different anitgenomes which will transcribe half of one then jump to the other anitgenome causing recombination, template switching is precise.
parvovirus hairpins
fold and self prime, replicates down strand, then an endonuclease cuts right before the hairpin and replication occurs down new strand displacing hairpin end in order to get a ds linear intermediate that isomerizes with double hairpins at the end when the
mutation rates viral DNA polynerases
with proofreading 10^-5 10^-8
How do you prevent HDV
HBV vaccination effective against HDVno specific HDV vaccination
what causes a pandemic?
introduction of a novel influenza A
How do you treat HDV?
Lamivudine (3tc) or penciclovir inhibit HBV RT, but thhey do Not inhibit the synthesis of HBs antigen. thus they cannot affect course of HDV antigen (???)
What is VpG
Viral protein covalently linked at 5 terminus of HAV RNA
what can IFN be used to treat?
Hep BHep CRhinovirus
The tumor suppressors targeted by DNA viruses regulate what cellular process
Cell cycle progression
Some of the nucleoside analogs used to inhibit HIV replication may also be efficacious against what virus
Hepatitis B virus
Cytomegalic inclusion disease
CMV. MC in-utero infection in US. Jaundice, hepatosplenomegaly, thrombocytic purpura, pneumonitis, CNS damage
virion
the infectious form of a virus as it exists outside the host cell, consisting of a nucleic acid core, a protein coat, and, in some species, an external envelope.
virus against interferon 8
Herpes simplex ativates a phosphatase that removes the phosphate that inactivates eIF-2a allowing translation to continue
baltimore classification system
1. Is the viral genome a mRNA 2. if not, can the -cell- synthesize mRNA from the viral genome 3. If not then the virion must contain a transcriptase to bring
virus against interferon 3
Adenovirous E1-a, Epstein barr, HepB terminal protein inhibit the signal transduction pathways that signal that interferon has bond to receptors
coding capacity
is the predicted sum of all the molecular weights of all the proteins encoded by the genome
defective interfering particles advantage
smaller, less time to replicate, interfere with WT but competing for rep resources, not transcribed like WT are only templates for replication
How is HAV spread
1) fecal-oral (anal sex, day care center)2) fecal contamination of source (concentrated in shellfish)
Describe mumps spikes
One has: H AND NA activityOther: F (fusing) activity
What is a virion made of?
NAproteinssometimes a lipid env w/glycoproteins
What is the range of clinical manifestations of HBV?
subclinical to fatal acute/fulminant
A 27-year-old female who contracts human papilloma virus type 16 is at risk for developing what
A chronic active viral infection
What are the Flaviviruses?
HCV, yellow fever, dengue, St. Louis encephalitis, West Nile virus
Diseases caused by HPV
Common warts (2, 4); Plantar warts (1); Condylomata acuminata; Benign genital warts (6, 11)(90%); Cervical intraepithelial neoplasia (16, 18). Find koilocytic cells in biopsy or PAP. DNA probes and PCR to determine strain.
Inteferon triggers
dsRNA from either annealing of + and - strands of RNA, dsRNA genomes, and overlapping genes in dsDNA genomes. Uncapped 5'ends are from antigenomes and other sources not common
classification of viruses
DNA vs RNA, symmetry, then naked or enveloped
coding capacity error
if the entire genome coded for one protein would not equal weight of genome and sine MW of viron is at least 50% it cannot be one protein
phi X 174
first virus to be known to have ssDNA
entry by enveloped viruses
by direct fusion (HIV) envelope fuses with membrane or receptor-mediated endocytosis (Flu A) clathrin coated pit acidification of vesicle causes fusion with vesicle and envelope. Lipophilic amines can buffer pH which no go on release.
what is the general deal with HDV?
Apparently an intrinsically defective RNA virus: no genes for its env nor for replication
what aeffects other than death can cell mediated immunity trigger?
local release of cytokines, chemokines, other factors that may cure cell without lysis
What happens wrt ag/ab complexes in HBV?
can deposit, causeing polyarteritis or glomerulonephritis
What are the +RNA virus families?
Calici, PEeCoRnA, Flavi, Toga, Corona, Retro. "Call Pico and Flava To Come Rap"
gene expression for -RNA viruses for euks 1
Rhabdoviruses (VSV vesicular stomatic virus, rabies), paramyxoviruses (measles, sendai) filoviruses (ebola) makes monocistronic +RNA from the genome with 5'CAP and poly A by encapsid transcriptase, these can then be translated
gene expression for +RNA viruses for euks 3
Coronaviruses (mouse hepatitis, SARS) uses another scheme where the first region is translated directly to get a replicase/transcriptase, this can than make an -RNA of different lengths ending with the complementary to the leader, from which the transcrip
virus against interferon 5
HIV, HepC proteins bind to and inhibit PKR directly, Polio protease cleaves PKR
What is Amantadine and Rimantadine?
Act on Flu A virus M2 protein (bokcing its role as an ion channel_. This prevents release of viral nucleocapsid into the cell cytoplasm from thhe endocytic vesicle. Infection is thus aborted.
An outbreak of a respiratory virus disease in chickens occurred in Hong Kong in 1998. Thisvirus was transmitted to the human population, resulting in several deaths. What is responsible for the emergence of epidemic outbreaks caused by this virus
Reassortment of viral genome segments in animal hosts
What is negative sense RNA?
Viral RNA the is complientary to mRNA and needs virion associated RNA-dependant RNA polymerase
describe and name members of the 2 subgroups of hepatitis
1) Bile secretion: HAV, HEV2) blood/fluid secretion: HBV, HCV, HDV
What do the envelope glycoproteins of HIV-1 and HIV-2 do
They bind to cellular receptors and mediate membrane fusion at the cell-surface
What is the deal with a infidelity of on in 10^-4?
Roughly 1 error per genome synthesized.If it were 10 -3, you'd get 10 errors per genome and probably no viable progeny virus
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