Viro lectures (definitions)

Question 1

The loss of infectivity through reaction of the virus with a specific antibody is

Answer 1

Virus neutralisation

Question 2

Heterotypic vaccines

Answer 2

vaccines that ar specific to another disease (e.g Marek´s disease - Turkey herpes)

Question 3

Ways of defence (vaccines)

Answer 3

General
- surveillance and control
- Animal hygiene
Specific
- In the environment
- In the host organism
Eradication (utrydde)

Question 4

Resistance of viruses to environmental condotions

Answer 4

• Dehydration
• High temperature
• Radiation
• Ionic enviroment

Question 5

Virus-cell interaction - Abortive infection

Answer 5

no virus release

Question 6

Virus-cell interaction - productive infection

Answer 6

virus release and shedding

Question 7

Cytopthic effects/cytopathogenic effects CPE

Answer 7

alterations in the morphology of cells due to virus infection (mainly observed in cell cultures). Usually detected by light microscopy

Question 8

Main types of CPE

Answer 8

• Inclusion body formation
• Cell rounding
• Syncytium formation (formed by enveloped viruses)
• Lymph cell nucleus (chromatin conglomeration, rearrangement)
• Cell vacuolisation
• Hemadsorption (viral hemagglutination is expressed on the surface of the inf. cells)

Question 9

Non-specific CPEs

Answer 9

Morphological changes independently from virus infections
- cell ageing
- alteration of pH range
- alteration of temp
- toxic components
- bacterial contamination
Differenciation
- compare with healthy cells

Question 10

Types of interactions between viruses

Answer 10

• Advantageous (positive for both)
• Disadvantageous (interference)
• Neutral (virtusexalation, no effect on each other)

Question 11

Recombination

Answer 11

Exchange of genetic information

Question 12

Complementation

Answer 12

Exchange of enzymes (mainly polymerase) between defective and competent viruses

Question 13

Phenotype mixing

Answer 13

Exchange of structural proteins

Question 14

Virusexalation

Answer 14

The viruses are able to multiplicity independently.
The simultaneous infection does not effect the multiplication, BUT changes the viral influence of the host cell or organism.
- Increased pathogenicity and CPE appears

Question 15

Mutation

Answer 15

Independent changes in the genetic material

Question 16

Types of mutation

Answer 16

• Spontaneous

- Induced (irradiation or mutagenic drugs)

Question 17

Forms of mutation

Answer 17

• Point mutation
• Sequence mutation
• Substitution
• Insertion
• Deletion
• Inversion

Question 18

Mutations - influences on the viral phenotype

Answer 18

• Antigenic change - escape mutants or antigenic drift (influenca)
• Changes in host species specificity - (e.g feline panleucopenia –> canine parvoenteritis, SIV–>HIV))
• Changes in organ specificity - (EHV1EHV4, IBRIPV)
• Different tissue tropism - (Bovine adenovirus=kidney/testicular cells)
• Viruelnce variants - (Newcastle disease, Avian influenca)
• Cytopathic effect, plaque formation - (Aujeszky´s disease, BVDV)
• Temperature optimum - (rhinoviruses, canine herpesvirus)

Question 19

Examples of double stranded RNA-viruses, dsRNA

Answer 19

Reoviridae

Birnaviridae

Question 20

Examples of single stranded positive sense RNA-viruses, +ssRNA

Answer 20

Picornaviridae
Caliciviridae
Togaviridae
Flaviviridae
Coronaviridae
Arteriviridae
Astroviridae

Question 21

Examples of single stranded negative sense RNA-viruses, -ssRNA

Answer 21

Orthomyoxyviridae
Paramyoxyviridae
Bornaviridae
Filoviridae
Rhabdoviridae
Arenaviridae
Bunyaviridae

Question 22

Viruses using revers transcriptase - RNA/DNA

Answer 22

Retroviridae, +ssRNA

Hepadnaviridae , ss/dsDNA

Question 23

Importance of eclipse strategies

Answer 23

Consequences on pathogenesis, epidemiology and detection of replicative intermediate forms (active virus multiplication). ANTI-VIRAL DRUG DEVELOPMENT
- HIV

Question 24

The Baltimore system

Answer 24

Classification of viral families
Type of NA and multiplication strategy
1. dsDNA
2. ssDNA
3. dsRNA
4. +ssRNA
5. - ssRNA
6. viruses using reverse transcriptase

Question 25

Examples of double stranded DNA-viruses, dsDNA

Answer 25

``` Papillomaviridae Polyomaviridae Adenoviridae Herpesviridae Poxviridae Asfarviridae ```

Question 26

Examples of single stranded DNA-viruses, ssDNA

Answer 26

Parvoviridae | Circoviridae

Question 27

Multiplication cycle of viruses

Answer 27

1. Adsorption (attachment to the host cell) 2. Penetration (entry into the host cell) 3. Decapsidation (NA release) 4. Eclipse (expression of genetic info) - Transcription, translation and NA replication 5. Maturation (assembly of progeny visions) 6. Release (evacuation from the host cell)

Question 28

General forms of penetration

Answer 28

Translocation Endocytosis Membrane fusion

Question 29

Alternative forms of penetration

Answer 29

Injection Sexfimbria Passive

Question 30

Decapsidation

Answer 30

Release of the NA from the capsid | Dangerous for the virus, but necessary for the transcription

Question 31

Eclipse

Answer 31

The expression and copy of the viral genetic information

Question 32

Maturation

Answer 32

Polypeptide to protein | - Glycosylation, dimer formation, AG development

Question 33

The role of viral proteins

Answer 33

- defence and targeting of the genome - shape of the virion - enzymes for multiplication - receptors

Question 34

Grouping of viral proteins

Answer 34

``` Structural proteins - Surface proteins - Core proteins Non-structural proteins (only prod. when a virus infect the cell) - Early, immediate early proteins - Late proteins ```

Question 35

Methods of viral protein investigation

Answer 35

- SDS-Polyacrylamide-gel electrophoresis (PAGE) - Immunobloting - Immunoperoxidase staining - Monoclonal AB production

Question 36

Viral lipids

Answer 36

Enveloped viruses, acquired from cellular membrane structures (budding) - phospholipid, cholesterol - positive virus-specific proteins, glycoproteins

Question 37

Viral carbohydrates

Answer 37

- Ribbose, deoxyribose (in the NA) | - Glycoproteins (on the surface)

Question 38

Molecular cloning of viral DNA

Answer 38

Propagation of virus DNA fragments in bacterial plasmids

Question 39

Morphology of viruses - Virion core

Answer 39

NA + proteins

Question 40

Morphology of viruses - Virion capsid

Answer 40

proteins

Question 41

Morphology of viruses - Virion +/- envelope

Answer 41

lipid membrane + proteins

Question 42

Morphology of viruses - Helical

Answer 42

NA + capsomers nucleocapsid No animal pathogen

Question 43

Morphology of viruses - Quasihelical

Answer 43

Enveloped viruses | - e.g Orthomyoxyviridae, Paramyoxyviridae, Rhabdoviridae

Question 44

Morphology of viruses - Icosahedral

Answer 44

Cubic, spherical Proteins arranged into capsomers, may have envelope - e.g Adenoviridae, Parvoviridae

Question 45

Morphology of viruses - Binal

Answer 45

Isahedral head + helical tail | Tailed bacteriophages

Question 46

Morphology of viruses - Complex

Answer 46

Poxviruses! No capsomers, complicated symmetri (de som ser ut som et bind på bildet)

Question 47

Morphology of viruses - Plenomorphic

Answer 47

Arenavirus! G type phages No capsid Always enveloped

Question 48

Virion

Answer 48

``` inert particles transferring genetic information Contain NA (DNA or RNA), protein, +/- lipid ```

Question 49

Vegetative virus

Answer 49

The infected cell

Question 50

Theories of the origin of viruses

Answer 50

- Cell degeneration | - Runaway cell components