Test 1 Flashcards
The first pandemic ever recorded was caused by _________ virus in 1590 when it spread from Russia to Europe.
Influenza Virus
The most lethal outbreak on record killed 50-100 million people in 1918. What virus caused it?
Influenza Virus
_________ was the first method used to immunize a person against Smallpox
Variolation/Inoculation
Who invented the smallpox vaccine by using “cowpox material”?
Edward Jenner
Who invented the rabies vaccine after injecting a rabbit’s brain with potassium hydroxide?
Louis Pasteur
Who invented the filter with pores smaller that bacteria?
Charles Chamberland
Who discovered the Tobacco Mosaic Virus?
Dmitri Ivanovski
DMitri –> Mosaic
Who discovered the cause of foot-and-mouth disease by passing the virus through a filter?
Loeffler and Frosch
Named “the conqueror of yellow fever”, who discovered that yellow fever was spread by mosquitoes?
Dr. Walter Reed
Who discovered oncogenic viruses and subsequently won a Nobel Prize for its discovery?
Peyton Rous
Which two scientists invented the Electron Microscope?
Ruska and Knoll
MERK
Microscope Electron invented by Ruska and Knoll
Woodruff, Goodpasture, and Burnet propagated this virus in embryonated eggs.
Fowlpox virus
What is the difference between a virion and a virus?
A virion is the complete, mature, infective form of a virus.
A virus is a broad, general term that describes any aspect of the infectious agent
What is the name for an infectious particle, smaller than any known viruses, and is an agent of plant disease?
Viriod
When was the last reported outbreak of the now eradicated virus Rinderpest?
Kenya in 2001
What is the very smallest virus, at 17 nm?
Porcine circovirus type 1
What is the very largest virus at 400 nm?
Pandoravirus
Spherical viruses, like Rotavirus have what kind of symmetry?
Cubic/Icosahedral
The ability of some viruses to alter their size or shape is called _________.
Pleiomorphism
What are the four methods used to determine morphology of Viruses?
EM
Cryo-EM
X-Ray Crystallography
NMR
Most viruses have 1 capsid. What is the exception?
Reoviruses have 2 capsids
What is the basic subunit protein of the viral capsid?
Capsomere
All animal nucleocapsids with helical symmetry have what?
A lipoprotein envelope
What kind of viruses have naked helical nucleocapsids?
Plant Viruses like the Tobacco Mosaic Virus
An Icosahedron is a solid with ____vertices, _____facets, and _____edges.
12 corners/vertices, 20 facets, 30 edges
The number of which type of capsomere, a penton or a hexon, varies with the virus group?
The # of hexons varies, the pentons are always at the 12 vertices
Only _______ viruses have icosahedral symmetry
Spherical
What is the formula for calculating T number?
T= (h)2 + (h)(k) + (k)2
h and k are jumps from penton to penton in different directions
What is the simplest icosahedron virus with its T number equal to 1 and 60 copies of capsomere protein?
Parvovirus
For Reoviridae, what is the T number for the outer capsid? The inner capsid?
Outer = 13 Inner = 2
Poxviruses and Bacteriophage have what kind of symmetry?
Complex symmetry
The capsid serves as a core of replication in what two viruses?
Reovirus and Retrovirus
Does a naked virus or an enveloped virus cause persistent infections?
Enveloped virus
What embedded envelope protein serves as the major antigens of the virus?
Glycoprotein (external)
What embedded envelope protein plays a crucial role in virus assembly?
Matrix Protein
Hemagglutin (HA) and Neuramidase (NP) are examples of what kind of envelope protein?
Viral envelope glycoproteins
Fusion proteins can be pH dependent or pH independent. Name two viruses with pH independent fusion proteins.
HIV and Measles
Which is easier to sterilize: enveloped or non-enveloped viruses?
Enveloped viruses are easier to sterilize
Which survives longer in the environment: enveloped or non-enveloped viruses?
Non-enveloped viruses survive longer in the environment
What kind of solvents can inactivate an enveloped virus?
Lipid solvents
Which sense of viral RNA is considered the infectious genome?
(+) sense viral RNA is the infectious genome
What mechanism of viral genetic diversity can lead to virus resistance to antiviral drugs?
Antigenic Drift can cause virus resistance.
Reassortment and Recombination are types of what mechanism of genetic diversity?
Reassortment and Recombination are forms of Antigenic SHIFT
What is the most important mechanism for high genetic diversity?
Reassortment – Antigenic Shift
Reassortment
“Look at dat ass in those genes”
What is the smallest, double stranded, circular DNA virus at 5 kbp?
Polyomaviridae
What is the largest, double stranded, linear DNA virus at 235 kbp?
Herpesvirinae
What is the smallest RNA virus at 2 kbp?
Deltavirus
What is the largest RNA virus at 30 kbp?
Coronaviridae
Viral proteins make up what percent of the virion?
50-70%
VP7 and VP4 are examples of ________ proteins that form the capsid in Rotavirus
VP7 and VP4 are structural proteins
NSP1 – NSP5 are examples of ________proteins in Rotavirus; proteins that are encoded by the virus but made in the host cell
NSP1 - NSP5 are nonstructural proteins
What are the 4 aberrations in virus morphology?
Incomplete virions
Defective virions
Pseudovirions
Pseudotypes
Gotta do<strong>DIPPs</strong>to get good<strong>abs</strong>
A virion without a nucleic acid, also known as an empty capsid, is called what?
Incomplete virion
A virus that cannon replicate because it lacks a full copy of genes is called what?
Defective virion
What is a DIP? What does it do?
Defective Interfering Particle
A defective virion that cannot replicate, but can interfere with other mature viruses entering cells
What type of aberration in virus morphology is used to deliver DNA vaccines? Why?
Pseudovirions
Because it is a nonviral genome inside a viral capsid
When two viruses infect the same cell and the genome of one virus gets into the capsid of the other, what is this called?
Pseudotypes
What are two names for the disease in pigs caused by Pestivirus?
Hog Cholera
Classical Swine Fever
The Baltimore Classification System categorizes viruses based on viral genome into how many groups?
7 groups
Double stranded DNA is classified into which group of the Baltimore Classification System?
Group 1
Single stranded DNA is classified into which group of the Baltimore Classification System?
Group 2
Double stranded RNA is classified into which group of the Baltimore Classification System?
Group 3
Single stranded RNA (+) sense is classified into which group of the Baltimore Classification System?
Group 4
Single stranded RNA (-) sense is classified into which group of the Baltimore Classification System?
Group 5
(+) single stranded RNA with a DNA intermediate is classified into which group of the Baltimore Classification System?
Group 6
Double stranded DNA with a single stranded RNA intermediate is classified into which group of the Baltimore Classification System?
Group 7
According to the ICTV, an order ends with the suffix ______?
–virales
According to the ICTV, a family ends with the suffix ______?
–viriDae
According to the ICTV, a subfamily ends with the suffix ______?
–viriNae
According to the ICTV, a genus ends with the suffix _______?
–virus
This family of viruses is characterized by having an envelope and being single stranded. This RNA virus family includes BVD, Hog Cholera, West Nile Virus, Louping Ill, and Equine Arteritis Virus. What is it?
Family Flaviviridae
Scrapie, Bovine Spongiform Encephalopathy, and Mad Cow Disease are all caused by what?
Prions
What are 4 ways to grow and cultivate viruses?
Cell/Tissue Culture
Inoculation in Embryonated Egg
Lab Animals
Organ Culture
Can viruses reproduce via binary fission?
NO
What are the 3 types of cell culture?
Primary cell culture
Secondary/Transfer cell culture
Cell lines
What kind of cell culture is best for isolating and propagating viruses?
Primary cell culture is best for isolating and propagting viruses
What kind of cell culture is used for making vaccines?
Primary cell culture is used for making vaccines
After the first subculture, a primary cell culture becomes a ______ _______
cell line
How many subcultures can you take from a primary cell culture?
5 - 20 subcultures
How many subcultures can you take from a Finite Diploid Cell Line?
100 subcultures
What are Finite Diploid Cell Lines derived from?
Embryos or Secondary Cell Cultures
WI-38 is a cell culture line made of fibroblasts, derived from the lung tissue of a 3 month old white female fetus. What kind of cell line is WI-38?
WI-38 is a Finite Diploid Cell Line
What kind of cell line exhibits *contact inhibition *and anchorage dependence?
Finite Diploid Cell Line
exhibits contact inibition and anchorage dependence
Continuous Cell Lines, also known as Immortal or Heteroploid Cell Lines, are derived from what kind of cells?
Continuous cell lines are derived
from cancer cells
Which type of cell line has a rapid growth rate, with doubling time from 12 to 24 hours?
Continuous cell line
HeLa Cells (Henrietta Lacks) are an example of what kind of cell line?
HeLa cells are an example of a
Continuous cell line
The FDA prohibits the use of this cell line in vaccines
Continuous cell lines
are prohibited from being used in vaccines
A cell in cell culture is seen with the following morphology:
Bipolar or multipolar
Elongated shape
Growing attached to a substrate
What kind of cell is it?
If the cell is bipolar or multipolar with an elongated shape and growing attached to a substrate, the cell is considered
Fibroblastic
A cell in cell culture is seen with the following morphology:
Polygonal in shape
Regular dimensions
Growing in patches attached to a substrate
What kind of cell is it?
A polygonal cell in culture with regular dimensions seen growing in patches attached to a substrate is an
Epithelial-like cell
A cell in cell culture is seen with the following morphology:
Spherical in shape
Growing in a suspension and not attached to any substrate
What kind of cell is it?
A spherically shaped cell seen growing in a suspension has
Lymphoblast-like
morphology
There are 3 kinds of morphologies seen in cells in culture: Fibroblastic, Epithelial-like, and Lymphoblast-like. Which one is the only one seen growing unattached to a substrate aka in a suspension?
Lymphoblast-like
What is the purpose of cell culture media?
Cell culture media provides all the necessary nutrients required for a cell to grow
Amino acids
Inorganic salts
Vitamins
Glucose
Serum is a source of what 4 things?
- Adhesion factors
- Attachment factors
- Nutrients
- Growth factors
What is the *most *widely used serum supplement?
FBS
(Fetal Bovine Serum)
Growth medium is ____% serum
Growth medium is *5-10% *serum
Maintenance Medium is ____% serum
Maintenance Medium is *0-2% *serum
If you’re using *Phenol Red pH Indicator *and your culture turns RED, what does this tell you about your culture?
RED = Basicity (Alkalinity)
Your culture has a pH greater than 7
If you’re using *Phenol Red pH Indicator *and your culture turns YELLOW, what does this tell you about your culture?
YELLOW = Acidic
Your culture has a pH less than 7
What is HEPES?
An organic buffer used to control the pH of culture
What % of CO2is considered normal for cell culture?
*4-10% *CO2 is considered normal
Gentamicin Sulfate and Kanamycin Monosulfate are examples of what?
Antimicrobial agents used to prevent contamination from
Bacteria, mycoplasma, yeast, and mold
Damage or morphological changes to host cells during virus invasion is called what?
Cytopathic Effect (CPE)
Cellular vacuolization, the opening of intercellular junctions, and cell detachment are examples of what?
Cytopathic Effect (CPE)
What kind of techniques would you use for rapid cell culture?
Use the Shell Vial Technique or Co-Cultivated Cell Technique for rapid cell culture
What type of rapid cell culture is ideal for the isolation of multiple viruses?
Co-Cultivated Cells Technique
What is **R-MIX **and what is it used for?
R-mix is a mixed monolayer of mink lung cells and human adenocarcinoma cells
It is used for Co-Cultivated Cell Technique in the detection of viral antigens
In egg candling, a method of cultivating viruses in eggs, what does a *blood ring *indicate?
A blood ring indicates a
dead embryo
;(
What are the 4 routes of egg inoculation?
Chorioallantoic Membrane Inoculation (CAM)
Amniotic Inoculation
Allantoic Inoculation
Yolk-Sac Inoculation
What does it mean if you see any of the following in an egg inoculation?
Death of embryo Urate deposits in mesonephros
Paralysis or sluggish movement Hemorrhage and congestion
Stunted growth Hemagglutins in embryonic fluid
Urate deposits in mesonephros Extracellular Membrane lesions
Pocks on Chorioallantoic Membrane (CAM)
All of these things indicate
virus growth
in egg inoculation
What type of centrifugation is based on buoyancy?
Isopycnic Centrifugation
is based on buoyancy
The point where the buoyant density of the particle equals the surrounding Density Gradient Medium is called what?
The *isopycnic point *is when
buoyant density = surrounding density of the medium
What two substances can you use for a
Density Gradient Medium?
Sucrose and Cesium chloride
can be used as
Density Gradient Mediums
The *lowest concentration *of a virus that still infects cells is the what?
The Virus Titer is
the LOWEST concentration of a virus that still infects cells
The *# of infectious units *per mL of sample is known as
Virus Titer
Virus Titer = #infectious units/mL of sample
Plaque Assays
Pock Assays
Endpoint Titration Methods
are examples of this type of viral quantification test
Biological Quantification Tests
include Plaque and Pock Assays
& Endpoint Titration Methods
What are the 5 Physical Quantification Tests?
Flow Cytometry
Hemagglutination
Immunological Assays (ELISA)
Quantitative PCR Analysis
EM Particle Count
Remember the Physical Quantification Tests by
using CHIPE
What is the most *direct *method to determine concentration of virus particles in solution?
TEM
(Transmission Electron Microscopy)
is the most direct method to determine concentration of virus particles in solution
What type of virus quantification is *ideal *for viruses with unique shapes?
TEM
(Transmission Electron Microscopy)
is great for viruses that have strange shapes!
Hemagglutination Assay, ELISA, HPLC, and SRID are all tests based on what property?
- Hemagglutination Assay
- ELISA
- HPLC (high performace liquid chromatography)
- SRID (Single Radial Immunodiffusion)
are all tests based on…
Antigen Concentration!
The *inverse *of the *greatest dilution *that completely agglutinates the RBC’s of the virus suspension is known as what?
**HA Titer **
HA Titer = 1 /(greatest agglutinated dilution)
What is the only quantification test based on gene expression?
**qPCR **
is based on gene expression
“OMG those genes are sooo Qute!”
A circular zone of necrotic cells
surrounded by viable cells
in a monolayer
is called?
Plaque
circular zone of necrotic cells surrounded by viable cells in a monolayer
What type of viral quantification test is considered the simplest and most accurate of the biological assays?
Monolayer Plaque Assay
is the simplest and most accurate!
What is the Principle of Plaque Assay?
The<em>Principle of Plaque Assay states that</em>
each plaque represents cell lysis
initiated by 1 viral particle
How do you calculate the Titer in a monolayer plaque assay?
take the average of the plaque counts
and multiply by
the reciprocal of the dilution selected
x + y / 2 = Average Plaque Count (APC)
1/ mL = Reciprocal Dilution (RD)
APC x RD = Titer
Necrotic area on chorioallantoic membrane (CAM) of an embryonated egg is known as
a POCK
necrotic area on CAM of an egg
What is the difference between a *plaque *and a *pock *?
A plaque is a necrotic area in a monolayer
A *pock *is a necrotic area in the CAM of an egg
What quantification test is used to determine *titers *of oncogenic viruses ?
Transformation Assay
is used to figure out the TITER of ONCOGENIC viruses
Oncogenic viruses *transform *cells in culture. What do you see with transformed cells?
**Loss of contact inhibition **
and
the cells will
heap-up on one another
What kind of assay is used for quantification of viruses that DO NOT form plaques?
Quantal Assays
used for viruses that do NOT form plaques
The virus dilution that affects 50% of test subjects is called the
Endpoint
What does TCID50 tell you?
It is the tissue culture infective dose that will infect 50% of cell monolayers presented with the virus
What is the MOI?
MOI is the multiplicity of infection
It is the average # of virus particles infecting each cell
How do you calculate TCID50?
What method is used to calculate it?
Use the Reed and Muench Method
(%infected above 50%) - 50
(%infected above 50%) - (%infected below 50%)
Then, add the # you get to the dilution above 50%
So if you get 0.3 for your answer and the dilution is 10-2, the Titer = 10-2.3 TCID50/0.1 mL
The *burst size *= the height of the curve
But what does this tell you?
The burst size or the height of the curve tells you
the # of virions released
In the One-Step Virus Growth Curve
the time between uncoating and appearance of virions in the cell
is called
The Eclipse Period
Can you detect viruses in the Eclipse Period?
NO, you cannot detect viruses during the Eclipse Period
In the One-Step Virus Growth Curve
the time before new infectious virus appears in medium
is called
The Latent Period
What kind of viruses are detectable during the Latent Period
in the One-Step Virus Growth Curve?
Only *intracellular virions *are detectable during the Latent Period
True or False
You can detect extracellular viruses during the Latent Period
in the One-Step Virus Growth Curve
FALSE
You can only detect *intracellular viruses *during the
Latent Period
What are the 6 steps of Virus Replication?
Attachment
Penetration
Uncoating
Synthesis of Viral mRNA
Assembly and Maturation
Release in large #s
APUSAR
A Puppy Uses Shoes As Relaxation
What are the 4 methods of Virus Penetration?
Endocytosis
Surface Fusion
Pore-Mediated
Antibody-Mediated
APES penetrate
What are the 2 types of Receptor-Mediated Endocytosis?
A1 Clathrin-mediated endocytosis
and
Caveolin-mediated endocytosis
What kind of receptor-mediated endocytosis causes the pH in the endosome to change to acidic?
A1-Clathrin-mediated endocytosis
involves a step where the pH changes to *acidic *
in the endosome
A1 = acidic
Which method of virus penetration is reserved for ONLY enveloped viruses?
Surface Fusion
is only achieved by *enveloped *viruses
What method of virus penetration is reserved for ONLY
nonenveloped viruses?
Pore-Mediated Penetration
is only accomplished by
nonenveloped viruses
Feline Infectious Peritonitis Virus uses which method of virus penetration?
FIP uses Antibody-Mediated Penetration
by using **CD13 **receptor and
IgG-Fcŷ
What stage of Virus Replication causes a
loss of infectivity of virions?
Uncoating
causes a loss of infectivity
What are the 3 steps of Primary RNA Transcript Processing?
Capping
Addition of Tails
Splicing
Capping refers to the addition of *7-methylguanosine *to the
___’ end of RNA
Capping refers to the addition of 7-methylguanosine to the
**5’ **end of RNA
How many residues does the 3’-poly-adenylated tail have?
The *3’-poly-adenylated tail *has 250 A residues
What is the 3’ cleavage sequence?
AAUAAA
After the AAUAAA cleavage sequence, how many nucleotides downstream does the actual cleavage occur?
10-35 nucleotides downstream from AAUAAA
What is it called when you remove introns and join exons?
Splicing
- Remove *Introns
- Join *Exons
(Remove and Intron have the same # of letters)
(Join and Exon have the same # of letters)
Does an intron or exon encode for amino acids?
Exons encode for amino acids
When every intron is spliced out and every exon is spliced in, what kind of splicing is it?
Constitutive Splicing
During the release step of virus replication, what happens to the host cell of a **naked **virus?
The host cell is lysed
for a naked virus
How are enveloped viruses released from their host cell during virus replication?
Enveloped viruses use **Budding **to release from their host cell
Monocistronic and Polycistronic are types of what?
Monocistronic and Polycistronic are types of
Viral mRNA
that encode either one or multiple polypeptides
What are the 4 methods of Cell-to-Cell Spread of Viruses?
Extracellular
Intercellular
Intercellular Transmission
Nuclear
What type of Cell-to-Cell Spread of Viruses
results in
rapid virus dissemination, evasion of the immune system, and persistent infections?
Intercellular spread
results in
rapid virus dissemination, evasion of the immune system, and persistent infections
What kind of Cell-to-Cell Spread of Viruses refers to the
viral genome being integrated into the host genome
and is subsequently passed down to the next generation
of host cells?
**Nuclear Spread **of Viruses
involves integration of viral genome into host cell genome
and generational transfer
