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Fundamentals of Virology
BIOT 316
Dr Natasha Anwar
Tues, Thurs 11.00 – 12.15
s416
Course Outline
• We will address the fundamentals of:
– properties,
– multiplication,
– molecular mechanisms,
– process of infection, and
– how viruses pose new threats to human and
animal health through emergence and evolution.
– we will focus primarily on viruses that are
pathogenic to animals.
Grading
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Think and learn principle
Quizzes 15%
Mid Term 30%
Final 30%
Presentations 15%
Written Assignment 10%
I
am
Virus
Viruses Infect....
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Humans
Other vertebrates
Invertebrates
Plants
Fungi
Bacteria
....they infect all cellular life forms
Can they be found anywhere else?
• Found in:
– soil,
– air and
– water (high conc in aqueous environments).
Nature
• Pathogenic
• Non pathogenic
Is the study of viruses important?
• Diseases
– Infections: can spread rapidly in a susceptible
population.
– Cancer
• Veterinary and plant virology?
Are they useful?
• Phage typing of bacteria. Some groups of bacteria,
such as some Salmonella species, are classified into
strains on the basis of the spectrum of phages to which
they are susceptible.
• Sources of enzymes. A number of enzymes used in
molecular biology are virus enzymes.
• Pesticides. Some insect pests are controlled with
baculoviruses and myxoma virus has been used to
control rabbits.
• Anti-bacterial agents. In the mid-20th century phages
were used to treat some bacterial infections of
humans. Interest waned with the discovery of
• Anti-cancer agents. Genetically modified strains
of viruses, such as herpes simplex virus and
vaccinia virus, are being investigated for
treatment of cancers.
• Gene vectors for protein production. Viruses such
as certain baculoviruses and adenoviruses are
used as vectors to take genes into animal cells
growing in culture.
• Gene vectors for treatment of genetic diseases.
Discoveries thanks to viruses
• A famous experiment carried by Alfred Hershey and
Martha Chase, and published in 1952, used phage T2
and E. coli to provide strong evidence that genes are
composed of DNA.
• The first enhancers to be characterized were in genes
of simian virus 40 (SV40).
• The first transcription factor to be characterized was
the transplantation (T) antigen of SV40.
• The first nuclear localization signal of a protein was
identified in the T antigen of SV40.
• Introns were discovered during studies of adenovirus
transcription.
Are Viruses Alive
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Yes =
No =
Somewhere in between =
Don’t know =
Basic Properties
• Size
– small
– The units in which virions are normally measured
are nanometres (1 nm = 10−9 m).
– 20-400nm
– Amongst the smallest are parvoviruses, with
diameters about 20 nm, while the microbemimicking virus (mimivirus), isolated from an
amoeba, is amongst the largest.
• Virions are not cells. They do not contain
organelles.
• Except for the virions of the arenaviruses,
which contain cell ribosomes that were
packaged when the virions were assembled.
Viruses have genes
• The virion contains the genome of the virus.
• Whereas the genomes of cells are composed
of double stranded DNA, there are four
possibilities for a virus genome:
– double-stranded DNA
– single-stranded DNA
– double-stranded RNA
– single-stranded RNA.