Lab2 Flashcards
Viruses that have surface proteins (haemagglutinins)?
Orthomyxoviridae, Paramyxoviridae, Coronaciridae, Parvoviridae
what makes lattice formation at the bottom of the tube?
The sedimentation of the virus-joined red blood cells
What can be demonstrated with haemagglutination test?
The method is not sensitive, so it is not perfect method to demonstrate the presence of low number of virions, but because of its simplicity it provides a very convenient assay if high concentration of virions are available
The haemagglutination titre is?
The end (highest) dilution of a virus suspension, where the haemagglutination still appears
What is the red blood cell suspension used for haemagglutination titre?
0.5-1% washed erythrocytes
What is haemagglutinins?
Surface proteins able to bind to erythrocytes
What is haemagglutination?
lattice-formation
What is used in haemagglutination inhibition tests?
HA unit of viruses
CPEs are alterations in the morphology of cells due to?
virus infection
CPE is mainly observed in?
cell cultures
CPE is usually a result of?
degenerative processes
ex of: toxic effect of adsorption?
Adenoviruses
ex of: Virus proteins inhibit cellular translation?
Herpes-, pox-, togaviruses
example of: Early proteins inhibit cellular nucleic acid transcription and replication?
herpes-, adenoviruses
ex of: Viral proteins damage the cytoplasmic membrane permability - osmotic change
herpesviruses
ex of: cytoskeleton depolimerization
herpes, paramyxoviruses
ex of: expression of fusion proteins
herpes, paramyxoviruses
Inclusion bodies appear at?
the site of assembly of nucleocapsid
Inclusion bodies are?
virus depositions
How can inclusion bodies be observed?
In stained cells (of cell cultures or organ sections):
- they have homogenous staining, surrounded by a narrow light stripe, the so called “halo” due to shrinkage after fixation
What causes the “halo”?
Shrinking after fixation. of stained inclusion bodies.
Intranuclear inclusion bodies is caused by?
DNA and sometimes RNA
Intranuclear inclusion bodies caused by DNA viruses?
Replicating in the nucleus.
Parvo-, papilloma-, polyoma-, adeno-, herpesviruses
Intranuclear inclusion bodies caused by RNA viruses?
Orthomyxo-, paramyxo-, arteri-, bornaviruses.
Cowdry-A, Cowdry-B types depends on?
the state of the synthesis of macromolecules.
How can Intranuclear inclusion bodies be stained?
Basophil = parvo Amphophil = adeno Eosinophil = herpes
When can caryomegalia and/or perichromasia be observed?
in case of high nuber of inclusion bodies or large inclusion bodies in the nucleus
Intracytoplasmic inclusion bodies caused by?
RNA viruses, sometimes DNA (if the viruses replicate in the cytoplasm )
What can be de DNA viruses replicating in the cytoplasm of Intracytoplasmic inclusion bodies?
Poxviruses, ASFV
How can Intracytoplasmic inclusion bodies be stained?
Eosinophil or rarely basophil (poxviruses) particles.
What are the Negri bodies and the Guarnieri bodies?
Pathognomic inclusion bodies of Intracytoplasmic inclusion bodies.
- Negri bodies: neuron cells, rabies
- Guarnieri bodies: epithelial cells, small pox
What is the reason for Cell rounding?
Cytoskeleton depolymerisation and a loss of electrolytes.
What is observed if the cell rounding is UNstained?
Double refraction, detachment and shrinkage