past general Flashcards
True/false: Prions are resistant to proteases
True
Prion pathogens do not contain?
Nucleic acid (proteins)
Affinity Chromatography uses?
Viruses adsorb to specific antibodies, rinsing to remove impurities and then elution with buffer.
Which disease was recently eradicated from earth?
Small pox and rinderpest
How did virus get its name?
A scientist used a filter whose pores were smaller than the bacteria so the bacteria was not filtered, but following further investigation, it was found that the filtrate contained a smaller form of infectious agent. This agent multiplies only in dividing cells and it was made of particles – it was called contagium vivum fluidum (soluble living germ) and later was simply called virus.
How are airborne viruses contracted?
Breathed in through the respiratory tract.
What is the given name for Goose Disease?
Goose Parvovirus (Derzsy’s Disease)
What virus is propagated in the Chorioallantoin?
Pox and Herpesvirus
What is eclipse?
Eclipse is the expression of genetic information. It is the step in virus multiplication involving transcription, translation and replication.
Genetic part of a virion?
DNA/RNA
The role of Rdrp in Retrovirus?
(RNA Dependent RNA Polymerase) Replication of RNA.
- How do bacteriophages get into the host cell?
Penetration.
What is a prion?
A prion is a small protein capable of infecting a cell and causing itself to replicate even though it contains no nucleic acid.
True/false:
Virions always contain lipids.
FALSE
True/false:
Virions with quasihelical nucleocapsids are enveloped.
true
Ture/false:
Virions with quasihelical capsids are never enveloped.
false
True/false:
Pleomorphic capsids may not have an envelope.
true
Please mark which is true:
a) Mutations are more frequent in cellular organisms than in viruses
b) The effects of mutations are always advantageous for viruses
c) Mutation may alter the host specificity of a virus
d) Mutant viruses cannot be used as vaccine strains.
c) Mutation may alter the host specificity of a virus
How do we call the process when the antigenic structure of a virus suddenly changes due to reassortment?
Antigenic shift.
How does the enveloped virus enter the cell?
Membrane fusion
True/false:
Viruses can only propagate in living cells.
True
Contact Inhibition:
When the cytoplasmic membrane edges of growing cells touches each other causing an inhibition to growth (forms a primary monolayer of cells)
What do you call the infective part of the virus?
Virion
Where do RNA viruses multiply?
In the cytoplasm
How to investigate virus neutralisation test?
Use blocking antibodies that will adsorb to the receptors of the cell so virus cant adsorb to the cell too.
- Constant virus varying serum dilution: Serial 2fold serum solution, add virus, incubate (antibodies will neutralise the virus), inoculate cell cultures, incubate, CPEs.
- Constant serum varying virus dilution: 2 Serial 10fold virus dilutions, add +and-serum, incubate, inoculate cell cultures, incubate, CPEs.
Monoclonal antibodies
Antibodies which are the same as they were produced by identical immune cells who were all clones of a unique parent cell.
What proteins are found in prions?
Cellular prion protein, Infectious prion protein.
What is the genetic part of the virion?
The nucleic acid (DNA/RNA)
Haemagglutination:
This is the clumping together of red blood cells. Tests include: Haemagglutination test, haemagglutination inhibition test.
Concentration of a virus sample?
Precipitation, adsorption, dialysis, ultrafiltration, pelletisation.
Virus titer:
- Infective titer: the highest dilution of the virus in which 50% CPEs occur.
- Haemagglutination titer: the highest dilution of the virus in which haemagglutination has not yet occurred.
Restriction nucleases:
cleave proteins at specific DNA sequences.
Cells removed from a monoculture:
Can then be used in a subculture and propagated further.
What type of sample is required for Ataxia in a horse?
Conjunctival and nasal swabs, liquor cerebrospinalis, EDTA blood. (Ataxia is a neurological sign consisting of a lack of coordinating movements)
Propagation of African Swine Fever:
experimental infection of living animals
Acridin Orange Test:
Tests for the presence of either ss/ds DNA/RNA.
-Green fluorescence when bound to dsDNA.
–Red fluorescence when bound to ssDNA or RNA.
Does a greenish-yellow colour mean a doublestranded virus?
Yes
Vaccines:
Live (attenuated, virulent, heterotypic, virus-vectored), inactivated, subunit, anti-idiotype.
Active Immunity:
Stimulation of an immune response by the body by a specific antigen (injecting a weaker live virus into the body so that the body itself must produce antibodies against the viral antigens), preventative method, long term immunity.
On which part of the virus is the lipid found?
Envelope.
PCR-Colour:
Green-dsDNA,
Red-ssDNA/RNA
What is the method of a hemolysis test using sheep blood?
- Haemagglutination Titre: serial 2fold dilution, add washed RBCs of appropriate species, incubate->titer is the highest dilution of virus where there is no haemagglutination as of yet.
- Haemagglutination inhibition: serial 2fold dilution of serum sample, add 4-8HA units of virus, incubate, add washed RBCs->titer is the highest dilution where there is no HA.
Amino Acid sequence of haemagluttinating protease cleavage site of Influenza A may cause?
Will cleave the Hemaglutinin of the virus-this must be cleaved by cellular proteases to be active as a fusion protein and cause infection.
