MICRB 415: EXAM 2

RDRP is packaged in the virion of Rhabdoviridae because (___) RNA is not functional in a eukaryotic cell and no RDRP that can be present to act on (___) RNA

(-) RNA

Rhabdoviridae Genome: (___) ssRNA genome, linear about ___-___ kb in size encodes ___-___ proteins

(-) ssRNA 11-15 kb 5-6 proteins

Ebola Virus Genome: 1. (___) ssRNA genome (linear) 2. about ___-___ kb in size 3. encodes ___ proteins

1. (-) ssRNA 2. 18-19 kb 3. 7 proteins

Norovirus Genome: 1. ___ open reading frames 2. Genome type: (___) ssRNA 3. Genome length is ___-___ kb 4. 5' end is covalently linked to a _____ protein 5. 3' end has _____ _____

1. 3 2. (+) 3. 7.4-8.4 kb 4. VPg 5. polyA tail

All of the following describe a feature of the pathogenesis of the filoviruses EXCEPT... A. induction of immunosuppression B. infection of macrophages and monocytes C. increased endothelial permeability D. induction of cytokine release E. loss of motor neuron control and movement

E

The intergenic regions in the paramyxovirus genome contains signals for all of the following processes EXCEPT... A. transcription reinitiation B. transcription termination C. Polyadenylation D. RNA polymerase disengagement E. Genome replication

E

Which of the following is an enzymatic function found in the nonstructural proteins of a coronavirus? A. Methyltransferase B. Helicase C. RNA-dependent RNA polymerase D. Ribonuclease E. All of the above

E

West Nile Virus

Enzootic cycle between birds and Culex mosquitoes Most common arboviral disease in the US No vaccine; no medicine; palliative care Incubation period 2-14 days Fever, headache, body aches, joint pains, vomiting, diarrhea, rash: Usually resolves within a week, Can persist for weeks or months Overall case fatality <1%

Spillover

Transmission of a zoonotic virus from an animal reservoir into humans

The 5'-end of the genome is covalently linked to _____, which is encoded by the 3B region of the viral genome.

VPg

~___% of WNND are fatal

~10

Coronavirus genome is ~___ kb _____ (___) _____ genome, _____ and _____ polyproteins, and 5' _____ 3' _____

~30 kb linear (+) ssRNA; ORF1a and ORF1b; 5' cap 3' poly A tail

Symptoms of Rabies Virus Disease:

"Furious Forms": most common; over 2-10 days; progresses from weakness/fever/headache, to anxiety/confusion/agitation, and finally delirium/abnormal behavior/hallucinations Alternative "Paralytic" Form: slow progression of muscle paralysis, then coma, then death * all forms are fatal once symptoms appear * < 10 documented cases of human survival from clinical rabies

Do the following questions apply to flaviviruses, hepaciviruses, both, or neither? 1. Uses a cap-independent mechanism of translation. 2. Establishes a persistent infection. 3. Genome is replicated by an RNA-dependent RNA polymerase. 4. A family of arboviruses. 5. Implicated as a cause of the common cold in Equatorial Kundu.

1. Hepacivirus 2. Hepacivirus 3. Both 4. Flaviviruses 5. Neither

Rabies Virus Transmission

1. Introduction to bite 2. Movement via nerves to brain 3. Viral replication and inflammation of the brain 4. Salivary glands and saliva *Phase when symptoms begin *Death within ~7 days of symptom onset

Rhabdoviridae Transcription: 1. _____ binds at leader (3' end) and sequentially transcribes each gene into mRNA by recognizing start and stop signals between each gene 2. mRNAs are _____ and _____ by L protein (RDRP) 3. mRNA and protein amounts _____ from left to right 4. Make large quantities of ___ proteins to coat all the viral genomes that get packaged into virions

1. RDRP 2. capped; polyadenylated 3. decrease 4. N (high N protein levels are more pathogenic than low levels)

The Coronavirus Lifecycle

1. Receptor Binding 2. Translation of RTC 3. Double-Membrane Vesicles 4. Transcription 5. RNA Replication 6. ER 7. ERGIC 8. Smooth-walled Vesicle

Paramyxovirus Genome Structure: 1. similar to _____ 2. ___-___ kb, encoding ___-___ genes 3. convention for (___) ssRNA viruses is to write them 3' to 5' 4. _____ is at the 3' end 5. _____ _____/_____ is at the 5' end 6. _____ on left (3' end of genome) and _____ on right (5' end of genome) 7. Some encode multiple genes from the P/C/V region of the genome via _____ _____ or _____ _____ _____ codons

1. Rhadoviruses 2. 15-19 kb; 6-10 genes 3. (-) ssRNA 4. Nucleocapsid (N) 5. L polymerase/RDRP 6. Leader; trailer 7. RNA editing; alternative ribosomal initiation

Key Strategies of Alphavirus: 1. The _____ serves as a template for both full-length and subgenomic RNA synthesis: Nonstructural proteins translated from genomic RNA (caliciviridae), Structural proteins translated from subgenomic RNAs (caliciviridae) 2. Polyprotein strategy; cleaved by both _____ and _____ proteases 3. 5' cap and translation is the same as for _____ mRNAs 4. _____ arrangement of envelope proteins 5. Used as _____ for vaccines, protein expression, etc.

1. antigenome 2. viral; host 3. host 4. Icosahedral 5. vectors

Key Strategies of Coronavirus 1. (+) RNA genome encodes both _____ and _____ _____ _____ 2. Forms a _____ _____ _____ (vesicles) 3. _____ is as complex as a cellular multi-subunit enzyme; includes proofreading activity 4. Contains _____ _____ _____ (___)

1. polyproteins; nested subgenomic RNAs a. subgenomic mRNAs made using discontinuous transcription → mostly structural proteins b. ORF1a and ORF1b made using ribosomal frame shifting → polyproteins encoding 16 nonstructural proteins 2. cytoplasmic replication organelle 3. Replicase 4. ER-Golgi intermediate compartment (ERGIC)

The _____ protein has an RNA-dependent RNA polymerase (RdRp) activity

3D

Picornavirus Genome

7.2-8.5 linear ssRNA (+) genome Polyadenylated (PolyA tract) on 3' end Single ORF → one polyprotein Viral genomic RNA has VPg protein on its 5' end Internal Ribosome Entry Site (IRES) IN 5' UTR

VP30 is required for Ebola virus replication A. True B. False

A

What is the one member of the togavirus family that is not transmitted by an arthropod vector: A. Rubella virus B. Chikungunya virus C. Sindbis virus D. Semliki Forest virus

A

Which of the following animals appears to be the reservoir for filovirus infections? A. bats B. domestic livestock C. insects D. primates E. raccoons

A

Most picornaviruses use _____ mechanism for translation

IRES-dependent

Taxonomy of Paramyxoviruses Order: Family: Subfamily: Genus: Species:

Order: Mononegavirales Family: Paramyxoviridae Subfamily: Paramyxovirinae; Pneumovirinae Genus (Paramyxovirinae): Morbillivirus (Species = Measles Virus); Rubalavirus (Mumps Virus); Henipavirus (Hendra Virus & Nipah Virus) Genus (Pneumovirinae): Orthopneumovirus (Human Respiratory Syncytial Virus)

E = ?

envelope

_____ are among the smallest viruses

Caliciviridae

CoV = ?

Coronavirus

These block fusion by:

Preventing formation of fusion intermediated Inhibiting enzymes required for conformational changes during fusing Blocking hydrophobic interaction necessary to form the hemifusion state

Reported issues of transmission of Zika Virus:

Primate-mosquito-human Human-mosquito-human (urban cycle) Perinatal, in utero, sexual, transfusion

How does poliovirus spread?

mostly by the fecal-oral route can also be spread through saliva or droplets from a sneeze or cough

VP = ?

vesicle packets

Picornaviridae Family Members: ___ genera of viruses that infect vertebrates

12

1 WNND case = ___-___ infections

140-250

Rhabdoviridae Viral Structure

180 nm long, ~ 75 nm wide Helical, enveloped, bullet-shaped virion

Incubation Period of Ebola Virus

2-21 day (average 8-10 days)

Spectrum of Human WNV Infections: ___-___% Asymptomatic - mild to no symptoms ___-___% "West Nile Fever" ~___% WNND

70-80% Asymptomatic 20-30% "West Nile Fever" ~1% WNND

RNA editing or stuttering produces GP and sGP: ___% unedited mRNA (nonstructural, secreted glycoprotein, sGP) ___% edited mRNA (protein membrane glycoprotein, GP)

80% unedited mRNA (nonstructural, secreted glycoprotein, sGP) 20% edited mRNA (protein membrane glycoprotein, GP)

2 doses of MMR (Measles, Mumps, & Rubella) are: ___% effective for measles (range ___%-___%) ___% effective for mumps (range ___%-___%) ___% effective for rubella (range ___%-___%)

97% effective for measles (range 67%-100%) 88% effective for mumps (range 31%-95%) 97% effective for rubella (range 94%-100%)

A patient presents with an arbovirus infection to which they've been exposed previously. However the last time they had barely any symptoms, and this time they are experiencing severe symptoms that require hospitalization. What do you think it is? A. Dengue virus, because this virus has multiple serotypes and sequential infections by different viral serotypes leads to more severe disease. B. Chikungunya virus, because the virus has a long incubation time, and the patient's symptoms have been slowly building over time. C. West Nile virus, because West Nile Neuroinvasive Disease (WNND) requires multiple rounds of infection to manifest symptoms.

A

Early studies of human noroviruses involved administering virus to adult volunteers. Where did researchers obtain norovirus for these studies? A. virus was directly filtered from stool of human volunteers B. virus had been cloned and propagated in cell culture C. virus was passaged in mice for multiple generations

A

Zoonotic Pathogens

A disease that can be transmitted to human beings from animals

DF = ?

differentiated

The ORF1b replicase polyprotein is produced by ribosomal frameshift, which is caused by pausing at a/an _____

pseudoknot

Rabies virus incubation period

weeks to months

Plus-Strand RNA Virus Life Cycle

1. Attachment 2. Endocytosis 3. Release of Genome (Uncoating) 4. Translation 5. Replication 6. Assembly 7. Release

Proposed Ebola virus Replication Cycle

1. Attachment 2. Macropinocytosis 3. Fusion at Endosomal Membrane 4. Negative-stranded RNA virus Transcription 5. Negative-stranded RNA virus Replication 6. Actin-dependent Outward Viral Transport 7 Budding via host ESCRT

Rhabdoviridae Life Cycle

1. Attachment 2. Receptor-Mediated Endocytosis 3. Membrane fusion and nucleocapsid release 4. Gene Transcription 5. Viral Protein Translation 6. Genome Replication 7. Virus assembly/budding

Propose Caliciviridae Replication Strategy

1. Entry 2. Uncoating 3. Translation: Nonstructural proteins encode the enzymatic functions 4. RNA Replication: (1) Initial genome, (2) Antisense genome, (3) Additional copies of (+) genomic RNA, (4) Shorter subgenomic (+) RNA (encode capsid proteins that make virions) 5. Maturation 6. Release

Key Strategies of Rhabdoviridae: 1. (-) ssRNA genome is transcribed into mRNA via _____ 2. Transcription - RDRP progresses from ___ to ___ synthesizing mRNA: stutters at end of each mRNA, adding a polyA tail; then either falls off, or continues and "scans" for next start; yield less and less mRNA for each gene, as RDRP gets further from 3' end 3. _____ order is critical for viral protein production in specific proportions, and for viral pathogenesis 4, ___ protein levels dictate the switch from transcription to replication (high "___" leads to genome replication: both the antigene (+ sense) and the full-length (- sense) are coated in "___" (nucleocapsid protein) 5. _____ virus spreads from the site of infection, via nerves, to reach the brain

1. RDRP 2. 3' to 5' 3. Gene 4. N 5. Rabies

Pramyxovirus Virion Size and Structure: 1. Virion is ~___-___ nm 2. _____ nucleocapsid surrounded by a _____ _____ 3. Polymerase (RDRP) is packaged in virion, in an RNP complex with ___, ___, and ___ (RDRP)

1. ~150-350 nm 2. Helical; lipid envelope 3. N, P, and L

Flavivirus Replication Cycle

1.Internalization 2. Fusion 3. Translation 4. RNA Replication (RNA-dependent RNA polymerase) 5. Assembly 6. Maturation 7. Secretion

How are the structural proteins in togaviruses expressed? A. They are translated from a subgenomic RNA. B. They are translated from the negative-sense strands after genome replication. C. They are translated directly from incoming genomes. D. None of the above are correct. E. They are only translated from newly synthesized full-length genomes.

A

Which one of these is not an arbovirus: A. Hepatitis C virus B. Japanese encephalitis virus C. West Nile virus D. Yellow fever virus E. Chikungunya virus

A

ARDS = ?

Acute Respiratory Distress Syndrome

_____ _____ (___) and _____ _____ _____ (___) are broad-spectrum antivirals

Antiviral peptides (AVPs); protein disulfide isomerase (PDIs)

BSL-4 facilities are readily available and convenient for research purposes. A. True B. False

B

In wildtype Ebola infections, only 20% of the envelope glycoprotein contains the transmembrane domain. Which of the following mechanisms controls the production of this membrane form of the protein? A. Alternative mRNA splicing B. RNA editing C. Ribosomal frame shifting D. Reading through a stop codon E. Proteolytic cleavage

B

What does the term arbovirus mean? A. It is transmitted by an arthropod. B. All of these are true. C. It is a vector-borne virus. D. For the examples discussed in class, it is likely to be a Togavirus or a Flavivirus.

B

Which cells were transfected to produce the Ebola ΔVP30 virus? A. BHK B. 293T C. Vero D. VeroVP30

B

Which one of these statements about Caliciviruses are TRUE? Calicivirus genomes contain three open reading frames. A. The major capsid protein of Noroviruses can form virus-like particles. B. All of these are true. C. The nonstructural proteins of Caliciviruses are translated as a polyprotein from a single ORF.

B

All of the following are members of the Mononegavirales EXCEPT... A. Rabies B. Measles C. Influenza D. Ebola E. Sendai Virus

C

All of the following diseases can be caused by members of the coronavirus family EXCEPT: A. Brochitis B. Hepatitis C. Arthritis D. Respiratory Disease E. Encephalitis

C

Which of the following viruses has NOT been associated with lethal human disease? A. Ebola Sudan B. Marburg C. Ebola Reston D. None of the above E. Ebola Zaire

C

Prolonged norovirus shedding & limited treatment options in immunocompromised patients: Current: ? Proposed: ?

Current: Supportive therapy Rehydration, total parenteral nutrition (TPN), antimotility agents Adjust levels/type of immunosuppressive therapy Proposed: licensed or new antiviral drugs Therapeutic antibodies Nitazoxanide

Zika Virus

Cycles in primates and Aedes mosquitoes 1 in 5 people infected become symptomatic No vaccine; no medicine; palliative care Incubation period 3-14 days Fever, rash, joint pain, and conjunctivitis (red eyes): Usually resolves within a week, Linked to microcephaly and other pregnancy-related issues

A number of passengers on a cruise ship have recently developed a gastrointestinal illness compatible with norovirus. It is your job to track down the source. What potential sources of infection should you consider? A. food sources B. water sources C. close contact with other infected individuals (person-to-person transmission) D. all of these E. contact with contaminated objects

D

In the paramyxoviruses, cleavage of the F0 protein into two subunits F1 and F2 is important for which of the following? A. glycosylation of the protein B. creation of the transmembrane domain C. formation of the envelope D. exposing the fusion peptide

D

Which of the following is a difference observed between the paramyxoviruses and the rhabdoviruses? A. One has a helical nucleocapsid and one has an icosahedral nucleocapsid B. One has a naked virion and one has an enveloped virion C. One has a negative-strand genome and one has a positive-strand genome D. One fuses the envelope at the plasma membrane and one fuses the envelope with the endocytotic membrane E. One packages the RNA-dependent RNA polymerase and the other doesn't

D

Two Types of Vector-Borne Spread

Enzootic vs. Epidemic: Dengue virus, Jungle cycle (enzootic) → Urban cycle (epidemic) Animal Reservoirs: West Nile virus, Primary Transmission Cycle → Incidental host

Virus Taxonomy (Caliciviridae) Family = ? Genus = ? Species = ?

Family = Caliciviridae Genus = Norovirus Species = Norwalk virus

Virus Taxonomy (Flaviviridae) Family = ? Genus = ? Species = ? Genus = ? Species = ?

Family = Flaviviridae Genus = Flavivirus Species = West Nile Virus Genus = Hepacivirus Species - Hepatitis C Virus

Common Routes of Norovirus Infection

Fecal/oral: Person-to-Person, Foodborne, Waterborne

Chikungunya Virus

First discovered in Tanzania in 1952: Name means "to be contorted" Transmitted by Aedes mosquitoes Global distribution: 60+ countries, Western hemisphere since 2013 Incubation period 3-7 days Usually fever and joint pain but also headache, muscle pain, rash: Symptoms can be severe and disabling, Can persist for months No vaccine or specific antivirals; just palliative care

_____ infect dendritic cells and/or keratinocytes and use these to move to the lymph node and then into the blood

Flaviviruses

Common Sites of Norovirus Infection

Food Retirement centers, nursing home, and hospitals: Nosocomial Infections Schools and daycares Vacation settings (cruise ship)

Receptor-binding triggers fusion protein in paramyxoviruses: ___ binding to receptor triggers an irreversible conformational change in ___ that enables fusion (Ex. sialic acid)

HN; F

Human Rabies Virus Vaccines

Imovax &RabAvert; one of several attenuated rabies virus strains it is also inactivated (rendered noninfectious) to increase safety delivered via intramuscular injection effective for both pre-exposure and post-exposure treatment

How contagious is norovirus?

Just a very small amount (few as 18 viral particles) on your food or hands can make you sick

Dengue Virus

Leading cause of illness among travelers returning from the tropics and subtropics 300 million infected annually; 40% of the world's population lives in areas at risk for dengue Four serotypes: A person can be infected up to 4 times in a lifetime, Severe illness more likely 2nd, 3rd, and 4th infection No specific antiviral; Dengvaxia vaccine available in some countries and approved in May 2019 for limited use by US FDA Incubation period 4-7 days Fever, headache, pain in eyes/joint/muscle/bone, rash: Usually resolves within a week, Dengue hemorrhagic fever - more rare; includes leaky vessels

Flaviviridae Virion Maturation: Morphogenesis

Maturation occurs in TGN (Trans-Golgi Network): Change in structure and cleavage of the outer-surface proteins (from spiky to smooth surface), Decrease in pH Outer protein lost after exocytosis Not known if capsid had a structure independent from the envelope glycoproteins (active area of research)

Vaccine-InducedProtection: Measles Immunity - ? Rubella Immunity - ? Mumps Immunity - ?

Measles Immunity - long-term and probably lifelong in most persons Rubella Immunity - one dose confers long-term, probably lifelong, protection Mumps Immunity - 1 dose of MMR vaccine provides persistent antibodies to mumps

Rhinovirus

Members: Human rhinovirus Over 100 serotypes Cause common cold Sensitive to low pH

Enterovirus

Members: Poliovirus & Coxsackievirus (A,B) Replicate in gastroenteritis tract Can cause meningitis, encephalitis, rashes, cardiac and muscular disease

5 Genera of Caliciviridae

Norovirus: Norwalk virus, Infect humans Sapovirus: Sapporo virus, Infect humans Lagovirus: Rabbit hemorrhagic disease virus, European brown hare syndrome virus Nebovirus: Newbury-2 virus (cows) Vesivirus: Vesicular exanthema of swine virus, Feline calicivirus

Norovirus Illness

Noroviruses are the major cause of nonbacterial epidemic gastroenteritis: Estimated 23 million cases/year in U.S. Common symptoms: diarrhea, vomiting, nausea, stomach pain Can also include fever, headache, body aches Incubation Time: 12-48 hours Viral Shedding: ~2 weeks No vaccine, no medication

Virus Taxonomy (Rhabdoviridae) Order = ? Family = ? Genus = ? Species = ?

Order = Mononegavirales Family = Rhabdoviridae Genus = Lyssavirus Species = Rabies virus

Virus Taxonomy (Filoviridae) Order: ? Family: ? Genus: ? Species: ?

Order: Mononegavirales Family: Filoviridae Genus: Ebolavirus (Zaire Ebola Virus, Reston Ebola Virus, Sudan Ebola Virus) & Marburgvirus (Marburgvirus)

_____ and _____ contain many of the animal-infecting viruses of Flaviviridae

Pestivirus; Pegivirus

Other (+) ssRNA viruses that induce cytoplasmic vesicles:

Picornaviruses Flaviviruses

_____ is not mosquito-transmitted

Rubella

_____ infections by a new Dengue virus serotype can lead to enhanced disease because of antibody-mediated entry/infection of ______

Secondary; monocytes

Alphavirus Virions

Spherical, enveloped, "fringe" of projections, 70-80 nm Envelope glycoproteins icosahedral symmetry

Flaviviridae Virion

Spherical, enveloped, 50 nm envelope (glycoproteins) have icosahedral symmetry

Coronavirus Structure

Spike protein (S) appears as a solar "corona" or crown and is likely sufficient for cell recognition Virion is enveloped and helical, not icosahedral: unusual for (+) sense RNA viruses Nucleocapsid is composed of N protein and genomic RNA

Human Norovirus Infection of B cells is stimulated by HBGA-expressing bacteria: _____ virus-positive stool initiates productive B cell _____ virus-positive stools fails to infect B cells HBGA-expressing bacteria can _____ infectivity of filtered stool

Unfiltered Filtered rescue

Why use subgenomic RNA for Alphavirus?

Virions require many copies of structural protein, which you can get from subgenomic RNA Enzymes can function repeatedly, structural proteins cannot

WNND = ?

West Nile Neuroinvasive Disease; Ex. Meningitis, Encephalitis, Acute Flaccid Paralysis

Members of Flaviviridae

Yellow fever virus (YFV) Dengue virus, types 1 and 4 (DENV-1 to DENV-4) Japanese encephalitis virus (JEV) West Nile Virus (WNV) Tick-borne encephalitis virus Hepatitis C virus (HCV) Animal-infecting viruses Zika virus St. Louis encephalitis

Reservoir

a population of organisms in which a pathogenic agent circulates in nature, not necessarily causing overt disease

Measles Disease

acute disease is best recognized by a rash: starts at hairline and works down; also fever, runny nose, cough incubation period: 7-14 days caused by paramyxovirus

MERS-CoV

aka Middle East Respiratory Syndrome Coronavirus initial reports and most cases in Arabian Peninsula spread by close contact; respiratory suspected no vaccine; no medicine; palliative care Incubation period 5-6 (range 2-14) days Fever, cough, shortness of breath: progressing to severe respiratory disease Case fatality ~30-40% thus far: often with underlying co-morbidities

SARS-CoV

aka severe acute respiratory syndrome 2003 outbreak (initiated in Asia; global spread) had case fatality ~9% Spread by respiratory droplets No vaccine; no medicine; palliative care Incubation period 2-7 days Fever headache, body aches, progressing to pneumonia Only some progresses to worst outcomes: older adults Multiple levels of severity

Nitazoxanide

an antiviral PDI drug for norovirus innate immune sensing

The majority of SARS-like coronaviruses have been isolated from _____

bats

VP1-4

capsid protein that all have a "jelly roll" fold and composed of an 8-stranded beta-barrel

CM = ?

convoluted membranes

Calici is derived from the Latin word for calyx, which means _____

cup

Replication of the viral genome takes place in the _____

cytoplasm

Coronavirus has nested mRNAS: different ___ boundary; same ___ end same leader sequence (60-100 bp) attached to each 5' end made by discontinuous _____ or ______ (template switching) uses TRS = _____ _____ _____

different 5' boundary; same 3' end transcription; recombination Transcription Regulatory Sequence

Subgenomic mRNAs are made using _____ _____

discontinuous transcription

Post-Exposure Prophylaxis (PEP)

disease prevention for rabies 5 doses of rabies vaccine over a 28 day period plus 1 dose of rabies immune globulin (antibody) for rapid, passive immunity can only abort the infection before the onset of clinical infections

DMV = ?

double-membrane vesicles

In the paramyxovirus life cycle, _____ doesn't occur (different from rhabdovirus) but _____ occurs (similar to rhabdovirus)

endocytosis; budding

Human Enteroids

ex vivo primary intestinal cultures derived from the crypts of human intestinal tissue (Ex. by biopsy of small intestine) can be used for replication of human norovirus and other enteric pathogens

Symptoms of Ebola Virus

fever, severe headache, muscle pain, weakness, fatigue, diarrhea, vomiting, abdominal (stomach) pain, unexplained hemorrhage (bleeding or bruising) *No vaccine (currently newly licensed vaccine); no medication; palliative care (IV fluids, oxygen)

HCC = ?

hepatocellular carcinoma; a liver cancer

The coronavirus genome is the _____ of all known RNA viruses.

largest

Bait Pellets

liquid vaccine in a sachet coated in fishmeal used for wildlife vaccination against rabies

Convoluted Membranes

loose sites of NS protein accumulation

M = ?

membrane; structural protein

Vesicle Packets

merged DMVs

MUC2 = _____

mucus

Syncytia

multiple cells fused together

Picornavirus Structure

naked icosahedral capsid, 30 nm diamater capsid with 60 copies each of: VP1, VP2, VP3, and VP4

Coronavirus transcription involves a _____ set of mRNAs.

nested

Rabies virus enter _____ at motor nerve endings that innervate the infected muscle

neurons; goes from periphery to the central nervous system

ND = _____ _____

not differentiated

N = ?

nucleocapsid; interacts with RNA

Raboral V-RG (Merial)

partially attenuated recombinant vaccinia virus (liquid) engineered to express the rabies virus glycoprotein vaccinia virus is the vaccine for smallpox, but it still presents a risk for the immunosuppressed

Ribosomal frame shifting of ORF1a and ORF1b: the _____ stalls the ribosome, providing the opportunity for the frameshift to occur _____ _____ allows the ribosome to shift +1 or -1 make lots of _____; only ~10% efficiency to make _____

pseudoknot slippery sequence ORF1a; ORF1b

RTC = ?

replicase transcriptase complex

Ebola virus Transmission

route(s) of transfer from natural reservoir to human unknown; likely via fluids/contact/consumption person-to-person transmission occurs by close personal contact; feeding, washing, medicating, or burial of an infected person; nosocomial (hospital) transmission via reuse or contaminated medical equipment (Ex. needles); sexual contact (virus in semen)

By expressing the major capsid proteins of Noroviruses, they _____ to virus-like particles

self-assemble; Suggest to vaccine development for the future

In picornaviruses, the poly protein is cleaved _____ (autocatalytic cleavage)

sequentially

Arthropod-Borne Viruses: The Arboviruses Yellow Fever Commission & Walter Reed (~1900): Yellow Fever is transferable via _____ from an infected individual, Agent could be transmitted by _____ Use of antibodies (_____) to group viruses Max Theiler (1930s): Vaccine development (___) for yellow fever virus

serum; mosquitoes serology 17D

Double-Membrane Vesicles

site of active RNA synthesis

Subacute Sclerosing Panencephalitis (SSPE)

slow, progressive disease of the central nervous system that results in memory loss, muscle spasms, and death several years after infection with a defective measles virus results in death years after initial infection

Picornaviruses are _____, _____, _____ _____ viruses.

small, non-enveloped, plus-strand RNA

The _____ protein of the virus gives the virus its corona.

spike

S = ?

spike; structural and receptor binding

sg = ?

subgenomic

ER-Golgi intermediate compartment (ERGIC)

unique location to assemble envelope glycoproteins, matrix, and nucleocapsid

Hematogenous Dissemination

viruses spreading via bloodstream

Key Strategies of Noroviruses: 1. (___) RNA genome makes a polyprotein 2. Polyprotein is cleaved to make _____ _____, _____, and _____ _____ 3. Viral protein (___) on 5' end Replication in cytoplasmic viral factories 4. _____ _____ encodes the capsid protein: Ribosomal termination-reinitiation produces _____ 5. Translation occurs without a _____ _____ or and an _____: Direct interaction of _____ with translation initiation factors

1. (+) 2. capsid proteins, proteinases, and replication proteins 3. Viral protein (VPg) 4. Subgenomic RNA; VP2 5. 5' cap; IRES; VPg

Alphavirus Genome: 1. Genome type: (___) ssRNA (_____) 2. Alphavirus: ___ kb; rubivirus (rubella virus): ___ kb 3. 5' end is _____ and _____ 4. 3' end has _____ _____ 5. 5' cap → _____ _____ → _____ _____ → 3' end poly(A) tail: Similar to calicivirus, Different from flavivirus and picornavirus

1. (+); (linear) 2. Alphavirus: 11 kb; rubivirus (rubella virus): 9 kb 3. capped; methylated 4. poly(A) tail 5. Nonstructural Proteins; Structural Proteins

Flavivirus Genome: 1. ___-___ kb linear (___) ssRNA genome 2. _____ at 5' end 3. No _____ _____ at 3'end 4. Single _____ → one _____ 5. 5' NTR → _____ _____ → _____ _____ → 3' NTR 6. Polyprotein - cleavage by viral and host _____

1. 10-12.3; (+) 2. Capped 3. poly(A) tail 4. ORF; polyproteins 5. Structural Proteins; Non-Structural Proteins 6. proteases

Viral proteins are expressed in a gradient for Paramyxovirus: 1. RDRP starts at ___ end of the genome 2. ___ gene mRNA is produced first and ___ is produced last 3. At intergenic sites, RDRP stalls and stutters to produce a _____ _____ 4. RDRP then either _____ or _____ _____ 5. This leads to a _____ of mRNA and protein being produced - same as Rhabdoviridae

1. 3' 2. N; L 3. polyA tail 4. continues; falls off

Alphavirus Replication

1. Entry/endocytosis 2. Uncoating 3. Translation (polyprotein and cleavage) 4. RDRP copies (+) strands into full-length (-) and (+) strands 5. Synthesis of subgenomic RNA 6. sgRNA translated: capsid + polyprotein 7. Structural polyprotein enters secretory pathway 8. Structural glycoproteins transported to surface 9. Same as #8 10. Assembly of capsid protein and (+) strand genomic RNA 11. Assembly budding at plasma membrane 12. Same as #11 13. Mature virions released

N protein levels contribute to switch from transcription to replication: 1. N protein is highly _____ 2. Sufficient levels of N protein _____ the polymerase from stopping at intergenic regions and _____ Poly-A tails 3. The subsequent read-through of the genome produces a (+) sense _____ which can then serve as a _____ for copying into (-) genome

1. expressed 2. block; producing 3. antigenome; template

Key Strategies of Filoviridae: 1. Subgenomic mRNAs are produced in a _____: largest amount of transcript is for nucleocapsid protein (Rhabdo/Paramyxo) 2. RNA editing or stuttering produces 2 glycoproteins (___ and ___) from the same gene 3. ___ protein levels control the switch from transcription to genome replication (Rhabdo/Paramyxo) 4. mRNAs are capped and polyadenylated by the ___ protein (RDRP) during synthesis

1. gradient 2. GP and sGP 3. N 4. L

Key Features of Paramyxoviruses: 1. Subgenomic mRNAs are produced in a _____ (Rhabdovirus) 2. ___ protein levels control the switch from transcription to genome replication 3. Fusion protein works at _____ pH, which means that the virus membrane can fuse at the plasma membrane. This can lead to _____ 4. Some use _____ _____ to add one or more nucleotides to the P/C/V gene, creating a new reading frame (and new resulting protein)

1. gradient 2. N protein 3. neutral; syncytia 4. RDRP stuttering

Ebola Virus Virions: 1. Filamentous, _____ virion 2. Virion is about ___ long x ___ nm diameter 3. As for other (-) ssRNA virus, the _____ is packaged in virion

1. helical 2. 970 nm; 80 nm 3. RDRP

Key Strategies of Picornaviruses: 1. (+) RNA genome makes a _____ 2. _____ is cleaved to make capsid proteins, proteinases, and replication proteins 3. _____ _____ (___) on 5' end as primer 4. Uses _____ to initiate translation 5. RNA _____ occurs in vesicles in cytoplasm 6. _____ is a model for the study of RNA dependent RNA polymerase and Capsid proteins VP1-4

1. polyprotein 2. Polyprotein 3. Viral protein (VPg) 4. IRES 5. replication 6. Poliovirus

Which of the following is an interesting feature of the envelope of a togavirus? A. There are 240 copies of the envelope protein in the envelope. B. The envelope proteins are arranged with icosahedral symmetry. C. The envelope only contains one type of protein. D. The envelope is inside the capsid.

B

How many times was the Ebola ΔVP30 virus passaged in VeroVP30 cells to test its genetic stability? A. 5 B. 10 C. 7 D. 20

C

The virions of filoviruses are very different than the virions of other negative-strand RNA viruses. Which of the following describe this difference? A. They use a helical nucleocapsid. B. They are enveloped. C. They are narrow and elongated. D. They are spherical. E. They don't contain a matrix protein.

C

Which of the following statements about paramyxoviruses is FALSE? A. The N protein protects the genome from ribonuclease digestion. B. The RNA-dependent RNA polymerase is a virion protein. C. The N protein can bind to a variable number of nucleotides in the genome. D. Naked genome-length RNA is never found within the cell. E. Every protein coded for in the genome is packaged into the virion.

C

Norovirus Virions: Surface has capsid protein of _____ and _____ domains Small (___-___ nm), _____/_____ particles Surface structure has a _____-like indentations

shell; protruding 27-35 nm; non-enveloped; naked cup