DNA Viruses Flashcards
Basic Virus Features
- _____, _____, ________ intracellular parasites
- Genome is either ______ or _____, never both
- ______: Outer protein shell that provides protection from the environment
- _______: Smaller repeating units that comprise the capsid
- ________ ______: Make pieces (nucleic acid and proteins) to make a whole virus
- Small; infectious; obligate
- DNA; RNA
- Capsid
- Capsomere
- Subunit Replication
-Viruses are named based on where they’re _______
-Isolated
- _______: Virus outbreak across numerous continents
- _______: Virus outbreak impacting the ENTIRE world
- _______: Contained within a continent
- Epidemic
- Pandemic
- Endemic
Zika
- Was an ________ in the world 55 years ago
- Came to the US from people returning from _______ Islands, only _____ home grown cases however
- ____, Zika, and _____ are from the same family of viruses that can be carried by ______ simultaneously
- Epidemic
- Caribbean; 2
- Chik; Dengue; mosquito
West Africa: Ebola Hemorrhagic Outbreak
- Ebola is a _______ disease
- ________ are NOT the natural host/_______ for Ebola
- Survivors will still have Ebola in the fluids of their ____ and _____ so it can spread easily during intercourse. The _____ are immune-privileged so Ebola will never leave and can cause ______
- The Ebola ______ in 2016 was the largest
- regional
- Humans; reservoir
- eyes; semen; eyes; blindness
- epidemic
Middle East Respiratory Syndrome (MERS)
- Derives from a ________
- Spread through close contact with ______
- Coronovirus
- camels
Mortality
- _____ is 50-90% lethal depending on the strain
- ______ is 23-90% lethal
- _____ Fever is 50% lethal
- ______ are how you sequester infections
-Ebola
-Marburg
-Lassa
Quarantines
Number of Viruses
- At least __________ viruses exist in mammals alone
- _____ _____: Found completely new viruses in humans and animals by examining fecal matter. ___% of new viral genomes are unknown viruses
- _____ to ____ viruses can cause human disease
- 320,000
- Viral Metagenomics; 99%
- 600-700
Viral History
- Zur Hausen won a Nobel Prize for finding that _____ _____ _____(___) is a major cause of oral cancer
- Montagnier and Barre-Sinoussie discovered ____ and won a Nobel Prize in 20008
- First cure for a viral disease was for ______-_ in 2015
- Human Papilloma Virus (HPV)
- HIV
- Hepatitis-C
Capsid Symmetry
- ______: Crystalline-like structure where the protein in the capsid determines the size and pattern. Composed of 20 ______ faces and the final product looks _______
- Can have ______ capsids too that are only found in _____ viruses
- _______: No symmetry. Seen with the ____ virus that causes Smallpox, molluscem contagiosum, and animal cowpox
- Icosahedral; triangular; spherical
- Helical; RNA
- Complex; Pox
Properties of Capsids and Envelopes
- ______ protect the nucleic acid from the environment, like the enzymes _______ and _______
- ___-________ viruses contain cell attachment proteins that allow for the ______ and ______ of specific receptors to certain target tissues
- ________ viruses contain a lipid envelope that contains glycoproteins used for attachment. The ______ membrane is sensitive and susceptible to ______ and _______, not true for ____-________ viruses
- Capsids can have ______, ______ or ______ symmetry
- Capsids; DNAse; RNAse
- Non-enveloped; targeting; uptake
- Enveloped; lipid; detergents; bleach; non-enveloped
- helical; icosahedral; complex
-The smaller the viral ______ the less proteins it ______ and the more ________ it is on the host to replicate
-genome; encodes; dependent
Viral Genomes
- Can be _____ or ______
- Can be _____, ______, or _____ in shape
- Can be _______ or _____ stranded
- ________ sense or _____ sense (antisense)
- DNA; RNA
- linear; circular; segmented
- single; double
- Positive; negative
Virus Detection, Quantification, and Diagnosis
- ______ ______ is the “gold standard”
- _____ ____ for virion quantification, this determines if something has a viral infection
- Direct observation via _______ _____(__)
- ________ via ELISA or immunofluorescence
- Can use _____ of viral nucleic acid if it cannot be seen with EM or typical CPE
- Virus Isolation
- Plaque Assay
- Electron Microscopy (EM)
- Antibodies
- PCR
Plaque Assay: Time Course
- Grow ______ cells and then add the virus
- Incubate for days and observe the ______ _____(__): the virus kills the cells. Can detect this by using _____ Stain with dye, only _____ cells are stained.
- The holes are _______, each one representing 1 virus infecting 1 cell
- mammalian
- cytopathic effect (CPE); CPE; live
- plaques
Viral Replication Cycle: Generic Virus Steps: 1. \_\_\_\_\_\_\_ 2. \_\_\_\_\_\_\_\_ 3. \_\_\_\_\_\_\_ of the capsid 4. \_\_\_\_\_\_\_ of early mRNA 5. \_\_\_\_\_\_\_\_ of early proteins 6. \_\_\_\_\_\_\_ of the viral genome 7. \_\_\_\_\_\_\_\_\_ of late mRNA 8. \_\_\_\_\_\_\_\_ of late proteins 9. Assembly of \_\_\_\_\_\_\_ 10. \_\_\_\_\_\_
- Attachment
- Penetration
- Uncoating
- Transcription
- Translation
- Replication
- Transcription
- Translation
- virions
- Release
Viral Entry into Cells
- _____-_____ fusion at the plasma membrane
- _________ help to open the plasma membrane, allowing for the entry of the ______ _____ in to the cell while leaving the ________ embedded in the cell’s plasma membrane
- Fusion of the _______ allows for entry into the cell where the virus uses the cell’s _______ to travel to the ______ membrane where the viral _____ is injected through nuclear _____ - Infusion via ________
- _________ take in the virus and the _____ decreases allowing for the release of the viral _____ into the cytoplasm
- ________ can take a naked virus in, which will then lyse the ________, and then dock onto the ________ membrane where it will insert its _______
- Viruses and ______ use _________ to travel in the host cell
- Lipid-lipid
- Glycoproteins; nucleic acid; glycoproteins
- Envelope; microtubules; nuclear; DNA; pores - Endocytosis
- Endosomes; pH; genome
- Endosomes; endosome; nuclear; genome
- endosomes; microtubules
Herpes Viruses
-____ viruses
-__DNA that is ~____ genes
-________ capsid with a lipid envelope
-__-____ with their host, well adjusted pathogens
-________, can effect all ______ and _______ species
-______ infections are a hallmark of herpes viruses, meaning herpes is _________
8 Human Herpes Viruses:
1. _____: Oral cold sores
2. ______: Genital herpes
3. ______: Chicken pox and shingles
4. _______: CMV retinitis and retardation
5/6. _____/_: Beta
7. ____: Mononucleosis and cancer
8. _____: Kaposi’s sarcoma and other cancers
-DNA
-dsDNA; 100
-Icosahedral
-Co-evolve
-Ubiquitous; vertebrates, invertebrate
-Latent; FOREVER
1. HSV1
2. HSV2
3. VZV
4. CMV
5/6. HHV6/7
7. EBV
8. HHV8
Herpes Envelope
- Contains 12 _______ in the envelope, ____ are involved in ____ into the cell. _______ C and B are involved in _______ to the cell
- Binds to cell receptors: ____ and ____-1
- Binding of glycoprotein ___ to the cell receptor initiates entry
- Glycoproteins __, ___/___ are essential for fusing 2 membranes. ____ is the fusogen
- The remaining ones are involved in ____ regulation
- glycoproteins; 5; entry; Glycoproteins; adsorption
- HVEM; Nectin-1
- D
- B; H/L;B
- immune
Synthetic Stage for Herpes Proteins and DNA
-______ occurs in the cytoplasm
3 Viral Proteins:
1. ________ _____ Proteins: First formed viral proteins that will assemble in the cytoplasm and return back to the nucleus to control viral DNA ______ and inhibit cell _______, set the stage for DNA ______
2. ______ Proteins: Second formed proteins that supply the enzymes (DNA polymerases for instance) that increase the rate of viral DNA synthesis, since ______ proteins and enzymes won’t work
3. ____ Proteins: Responsible for the production/assembly of the structural proteins inside the _______ so the virus can be assembled
-All the viral _____ leaves the nucleus to go to the cytoplasm to be ________, and the resulting _______ return to the nucleus to function
- Uncoating
1. Immediate Early; synthesis; function; replication
2. Early; host
3. Late; nucleus - mRNA; translated; proteins
-The ideal drug inhibits virus _______
-replication
Herpesvirus Capsid Assembly
- Capsid assembly occurs in the ____
- The __________ step occurs outside of the _______
- _______ organize the capsomere components into units, and will be degraded by viral _______ once the capsid is formed allowing for the _____ to be inserted
- A ______ helps to insert the _____ into the virus. _______: Capsid containing nucleic acid
- The virus synthesizes and releases ______ to modify the _____ ____ of the nuclear membrane. ______ were being developed on the _____ ______ of the nuclear membrane and get attached once the capsid buds forming the ________ Envelope.
- The _______ Envelope buds with the _______ ______ being modified with _______ Proteins and the glycoproteins are removed
- _______ Proteins allow the virion to bud with the _____ and obtain the final _______ needed to become a fully _______ and _______ virion
- Become active and live ______ once they bud from the ________ membrane
- nucleus
- maturation; nucleus
- Scaffolds; proteases; DNA
- pump; DNA; Nucleocapsid
- proteins; inner leaflet; Glycoproteins; outer leaflet; Primary
- Primary; Endoplasmic Reticulum; Tegument
- Tegument; Golgi; glycoproteins; functional; infectious
- viruses; cellular
HSV Infection: Multi-nucleated Giant Cells Syncytia
- Viral glycoproteins can ____ cells together to make a massive cell with many _____ containing active virions
- The ______ of the infected cell has all of its ____ degraded so it only interacts with viral ______
- _________ will fuse together and viruses will stabilize active ________ to ensure they can generate enough energy for viral _________
- fuse; vesicles
- nucleus; DNA; DNA
- Mitochondria; mitochondria; replication
Herpes Simplex Virus (HSV) Infections
- _____ many types of cells
- ___ entry glycoproteins
- ___ protein receptors on cells
- 2 _____ of entry
- _____ _____: First exposure to the virus that will effect the _____, _____, and ____. _____ 1: Above the naval and is 60% of all cases, and _____ ______ 2: below the naval
- ________: Virus moves up the axons through the __________ Ganglia (V1, V2, and V3) as a piece of ______ DNA in the neurons. ______ inserted into the genome, and is reactivated by a ________. ____ 1: impacts the Trigeminal Nerve, and _____ 2: is sacral
- _______ ______: Reactivation of the disease typically where it first occurred. Appears as a ______ sore, _______: Viral blindness, and _____ ______: Was a problem in dentistry where dentists would get infected, decreased because of gloves
- Infects
- 4
- 2
- pathways
- Primary Infection; mouth; skin; eyes; Type I; Genital Type
- Latent; Trigeminal; circular; NOT; stimulus; Type 1; Type 2
- Recurrent Infection; cold; keratitis; Whitlow’s Finger
Latent, Recurrent Infections
- _______: No symptoms
- People with _____ and _____ lesions are constantly secreting virus
- Initial ____ infection followed by quiescence
- Host ____ ____ clears most of the virus but some will persist, often in immunologically ____ sites
- ______: Immune suppression that reactivates latent virus, may or may not produce ________
- Shedding
- oral; genital
- acute
- immune response; protected
- Stress; symptoms
Controlling Viral Diseases
- _______: Provide enough protein particles so an individual can present an immune response to combat the disease
- Using _____
- Vaccines
- drugs
Mechanism of Neutralization: Ab to Glycoprotein D
1. _______ can bind to surface receptors of the cell and virus, this prevents viral _____
2. Subunit ________ __ Vaccine creates antibodies that will aggregate viruses into _____ the body can recognize and remove
3. __________ cell lysis (______ Immune System) recognizes the antibody interaction between a virus and cell, the ____ gets destroyed
Methods of Viral Evasion
-Production of ____-________ proteins
-Counter measures exist for every _____ _____
- Antibodies; entry
- Glycoprotein D; complexes
- Complement; Innate; cell
- anti-complement
- immune response
Antiviral: 3 Classes of Drugs for herpes
- ________ Analogues
- ______ Inhibitor of DNA Synthesis
- _______ Inhibitors
- Requires _______ _______ to avoid harming the host
- Nucleoside
- Acyclovir
- Protease
- selective toxicity
Targets for Drug Intervention
- Prevent viral ______ into cells
- Prevent virus _____
- Prevent virus exit from the _____
- Degradation of the virus in the _____
- Can _______ the virus once it leaves
- entry
- replication
- nucleus
- cytoplasm
- aggregate
Nucleoside Analogues
- An _____ copy of a nucleoside
- Prevents ______ of DNA or RNA when incorporated
- Can take the place of _______ nucleosides, _____ the completion of a viral DNA chain during infection of a new cell by _____
- Can alter the _____ or add a ______ group
- ________: A triple fluorine derivative that is the best analog
- artificial
- replication
- natural; blocking; HIV
- sugar; prosthetic
- Trifluorothymidine
- _________: only used in the eye to treat HSV since the cells of the eye are quiescent
- Analogues must be uptaken in the eye since no ____ ______ occurs
- Trifluridine
- cell division
-______ Used to decrease the pain, and will speed up the healing of sores in those with HSV. Prevents outbreaks of ______ herpes (may not stop the ______ however) and is a _______ analogue. Prevents ______ of HSV by preventing it from spreading
-Acyclovir; genital; spread; nucleoside; recurrence
Mechanism of Acyclovir
- ______ _____: A viral specific enzyme used in viral DNA synthesis and is not _______ by the host
- Inhibits viral DNA _________
- Virus evades inhibition by mutating ______ ______ so Acyclovir isn’t incorporated by it
- Thymidine Kinase; recognized
- Polymerase
- Thymidine Kinase
Protease Inhibitors
-Stop viral _________ by preventing ______ ____ from being incorporated into the virion
-replication; nucleic acids
Adenovirus
-Typically the viral _____ for gene delivery
-Insert the _____ genes so the virus will replicate them and _______ them to specific ______
-___-_______ DNA virus that is persistant
-Cause of ___/____-like respiratory disease
Problems with Viral Vectors:
-_____ _____ will make it difficult for the virus to enter the cell without it being eliminated
Solutions:
-Use a _____- version of the virus so the primate receptors are recognized, and since it’s new to us no ______ immune response has been built against it
- vector
- desired; deliver; targets
- Non-enveloped
- eye/cold
- Immune response
- chimp; prior
Adenovirus Capisd Structure
- Roughly ___kb
-________ symmetry, with projecting _____ that interact with cell receptors
Genome:
-Single ____ molecule of dsDNA that encodes for ____ proteins
-36
-Icosahedral; fibers
-linear
40
Adenovirus Entry and Uncoating
- ______ bind cell receptor ____-cell adhesion proteins
- _____ base binds integrin receptors (__ receptors)
- Virus enters an _____ where the _____ and ____ are removed, losing its infectivity
- Capsid docks at the nuclear ____, where DNA is inserted and the virus gets assembled in the _____
- Entire process takes ___ minutes
- Fibers; CAR
- Penton; 2
- Endosome; fibers; pentons
- pore; nucleus
- 30
Adenovirus Capsid Assembly
- Proteins ___ and ___ form the penton
- Protein ___ forms the Hexon Trimer
- _______ are required to form the capsid, but the DNA is inserted before the ______ are degraded
- __________ inhibitors are ideal for stopping its replication, the virion won’t _______ this way, but the ___ still dies
- 4; 3
- 2
- Scaffolds; scaffolds
- Protease; mature; cell
Adenovirus: Persistent Infection
-________ is inapparent
-Remains with the host for prolonged ______ or for life
-Transmission is ______, meaning it’s only passed from population members, and not _______
-Virus _______ reintroduces the virus into a new population
Other Persistent DNA Viruses:
-_______
-_____ _
-_____ (CMV and EBV), HSV is latent and never leaves so it too is technically “persistent”
- Infection
- periods
- horizontal; genetically
- shedding
- Papillomavirus
- Hepatitis B
- Herpes
Papova Viruses
- Stands for: _______, _____, ______ vacuolating viruses
- No ____ relationship
- All are small _____ icosahedral viruses
- _______ dsDNA
- All replicate in the _____
- Papilloma; Polyoma; Simian
- genomic
- naked
- Circular
- nucleus
Papilloma Viruses
- Cause _______ lesions, aka warts
- Target _______ epithelial cells
- Viral DNA persists in tissues as an ________, not integrated into the chromosome
- Gene expression only in ________ _____ cells of the epidermis
- Major causative agent for human ______ and ____ and _____ cancers
- proliferative
- squamous
- episome
- terminally differentiated
- cervical; head; neck
Papilloma Virus Replication
- Requires cell ________ to replicate
- Virus infection takes place at the layer just above the _______ _______
- Virion assembly occurs in ______ ________ keratinocytes, the cells are ______ so they result in the build up of keratinized dead skin cells
- Requires _______ cells to replicate
- differentiation
- basal lamina
- terminally differentiated; hypoplastic
- differentiating
-_________ and ______ cancers are more likely to impact men over women
-Head; neck
Human Papilloma Vaccine
-_____ ___: Major capsid protein used as an antigen for immunization
-___ protein is expressed in yeast or insect cells using recombinant technology, and they ____-_____ into virus-like particles (VLP)
Virus-like Particles:
-______-_____ _ Vaccine: Defends against 18 HPV strains including strains _ and __ which cause 90% of _______ warts, and strains 18 and 16 that are linked to cancer
-___-______ Vaccine: Defends against strains 16 and 18 along with a few lesser culprits
-________ Vaccine: Example of another vaccine defending against numerous strains of a virus
- HPV L1
- L1; self-assemble
- Merck-Gardasil 9; 6; 11; genital
- GSK-Cervarix
- Pneumacoccal
Types of Hepatitis Viruses
- ____ _: Can only be obtained by eating fecal matter, huge ____ in the US now
- ____ _/__: Both are serum based and spread through serum transmission and ________ transmission
- _____: Non-A non-B hepatitis
- Medication to cure Hepatitis __
- Chronic infection for Hep __, ___, and __
- Hep A; epidemic
- Hep B/D; sexual
- NANB
- C
- B; C; D
Hepatitis B Virus Modes of Transmission
- ______: Sex workers and homosexuals are particularly at risk
- _______: Health workers are at an increased risk
- ______: Mothers who are positive are likely to transmit it to their offspring, the _____ mean of Hep B transmission
- Infection can result in a short term, _____ infection that is self-limiting, or a ______ life-time infection
- Sexual
- Parenteral
- Perinatal; main
- acute; chronic
Hepatitis Structure
-Hep B vaccines introduce ___ antigen
-HBs
Hepatitis B
- A DNA virus with a ______ for its lifecycle that creates a _______ RNA which gets transcribed to DNA serving as a template
- A DNA virus acting like a __________
- Transcriptase; pregenome
- retrovirus
Drug Treatment for Hep B
- _______ Hep B infections are short-lived and go away on their own
- _______ Hep B infections are treated to reduce the risk of _____ disease and prevent transmission
- ________: Helps fight the infection and slow liver damage
- ______ transplant if the ____ is severely damaged
- Acute
- Chronic; liver
- Lamivudine
- Liver; liver
