General properties of Virus Flashcards
Parts of the virus
Nucleocapsid- Nucleic acid + capsid (protein coat covering it)
Tegument- proteinaceous structure between capsid and envelope
Envelope- Lipid containing membrane surrounding virus
Peplomers- virus encoded glycoproteins on outer surface as projections
Father of virology
Martinus beijerinck
Proposed contagium vivum fluidum (living infectious fluid) when studying mosaic disease in Tobacco mosaic plant
- Largest DNA virus
- Largest RNA virus
- Smallest DNA virus
- Smallest RNA virus
- Pox virus
- Filovirus
- Parvovirus
- Picornavirus
All DNA viruses are double stranded except
Parvovirus
(single stranded DNA)
All RNA viruses are single stranded except
Reovirus- dsRNA virus
Retrovirus- 2 copies of ssRNA
Enveloped virus characteristics
Bile sensitive
Heat labile
Ether sensitive
Pleomorphic
Non enveloped is opp of this
Lipid of enveloped virus is ____ origin and protein is _____ coded
Host cell origin
virus coded
Non enveloped DNA viruses
Adenovirus
Parvovirus
Non enveloped RNA viruses
‘PARCH-a-eee’
Picornavirus
Astrovirus
Reovirus
Calcivirus
Hep A and E
Enveloped DNA viruses
‘HHP’
Herpes
Hep B
Poxvirus
Enveloped RNA virus
‘Hey Ruby, check Dengue’s Japanese Kite Zooming’
Hep C
Rubella
Chikungunya
Dengue
Japanese Enceph virus
Kyasanur forest disease virus
Zika virus
What is solvent/ detergent plasma?
aka SD plasma
made from plasma collected from may people and then processed with solvents in an attempt to remove viruses
What is segmented genome?
A genome divided into multiple pieces with intact genes so these can be exchanged between related viruses
This recombination is called Reassortment. It forms unique chimeric genome which results in evolved virus with increased fitness
It can be responsible for antigenic shifts
Examples of segmented viruses
‘ARBO’
Arenavirus- 2 segments
Rotavirus- 11 segments
Bunyavirus- 3 segments
Orthomyxovirus- 8 segments
Molluscum contagiosum is a part of ____ family
Poxviridae
All DNA viruses have replication process in ____ except ______ (which is in cytoplasm)
Nucleus except Poxvirus (which is in cytoplasm)
All RNA viruses have replication in _______ except ________ which is in nucleus
Cytoplasm
Orthomyxovirus, Retrovirus
What is a negative stranded RNA
ssRNA with 3’-5’ RNA is a negative strand RNA
What does negative strand RNA use to replicate?
RNA replicase/ RNA dependent RNA polymerase
Examples of negative stranded RNA viruses
‘Always Bring Da Polymerase OR Fail to Replicate’
Arenavirus
Bunyavirus
Deltavirus
Paramyxovirus
Orthomyxovirus
Filovirus
Rhabdovirus
Ebola virus is spread by
Direct contact with infected body fluids
Ebola virus
Filamentous virus
single stranded RNA
Shape of
1. Adenovirus
2. Tobacco mosaic virus
3. Poxvirus
- Space ship
- Rod shaped
- Brick shaped
COVID 19 symmetry
Enveloped helical symmetry
Naked icosahedral viruses example
Adenovirus
Poliovirus
Hep A
Enveloped helical viruses examples
Coronavirus
Influenza
Parainfluenza
Rabies
Mumps
Measles
Complex structure of virus seen in
Pox virus
Study of viral symmetry by electron microscopy requires use of ____ stains for example ____.
Heavy metal stains
Eg. Potassium phosphotungstate
It is a form of negative staining
Most efficient symmetry
Icosahedral
Icosahedron has ___ faces and __ vertices
20
12
Why is it not possible for empty helical particles to form?
Periodic interactions are required between capsid protein and nucleic acid for stable helical symmetry
Enveloped icosahedral symmetry shown by
Herpes
Yellow fever virus
Rubella virus
Allantoic cavity inoculation is done for growth and replication of ___ virus
Influenza, Mumps
Amniotic cavity also used but its difficult to access
Yolk sac inoculation of virus for growth and replication is done for
Herpes simplex virus
It can also be grown in Chorioallantoic membrane
Chorioallantoic membrane inoculation is done for ____ virus growth
HSV, Poxvirus
Suckling mice inoculation is done for growth of ___ viru
Coxsackie
Arbovirus
Types of tissue lines with examples
Primary cell lines:
1. Rhesus kidney cell line,
2. Human amniotic cell line,
3. chick embryo fibroblast
Secondary cell lines:
1. Human fibroblast cell line
2. MRC-5
3. WI-38
Continuous cell lines:
1. HeLa cell lines
2. HEp-2
3. Vero
4. KB
Methods of assay of infectivity of viruses
Physical
Biological
Physical methods of assay of infectivity of viruses
They can estimate total viral count
They cannot differentiate between infectious and non infectious viral particles
Examples; RT-PCR, Electron microscopy, Antigen detection assay
Biological methods for assay of infectivity of viruses
They can estimate total viral count and can detect infectious virus
Eg: Qualitative- endpoint biological assay
Quantitative- plaque and pock assay
Cytopathic effects caused by viruses means
Morphological changes in cells that are caused by viruses is called cytopathic effects.
These viruses are called Cytopathogenic viruses. They can be detected by light microscope
Examples of cytopathogenic viruses
Rapid crenation and degeneration of cells by Enterovirus
Synctitium/ Multinucleated giant cell formation by Measles, Mumps, RSV
Discrete focal degeneration by HSV
Large granular clumps resembling grapes by Adenovirus
Vacuolation of cytoplasm by Simian virus 40
