An Introduction to Virology

LECTURE 1:

Viro100: Virology3 Credit hoursNUST Centre of Virology & Immunology

Course Work

• Quizzes 5%• Class Participation & Attendance 5%• Presentation & Assignment 10%• First Sessional 20%• Second Sessional 20%• Final Term 40%

The Nobel Prize in Physiology or Medicine

2008is awarded with one half to

Harald zur Hausen for his discovery of

“human papilloma viruses causing cervical cancer”and the other half jointly toFrançoise Barré-Sinoussi

and Luc Montagnierfor their discovery of

“human immunodeficiency virus”

Major topics in General Virology

• What is virus?• Virus growth in cells• Virus interaction with whole organism• Viruses and diseases• Antiviral pharmacology and applied virology

Viruses are every where !!!!• We carry viral genomes as part of our own genome

material• Every milliliter of seawater has more than a million

virus particles• More than 1030 bacteriophage particles in the

world’s water supply• A bacteriophage particle weighs about a femtogram

(10-15 grams)• 1030 X 10-15 = the biomass on the planet of

BACTERIAL VIRUSES ALONE exceeds the biomass of elephants by more than 1000 fold

• There are ~1016 HIV genomes on the planet today• With this number of genomes, it is highly probable

that HIV genomes exist that are resistant to every one of the antiviral drugs that we have now, Or EVER WILL HAVE!

• Each of you in this room is probably infected with at least 2 of the 9 known herpes viruses

• Each of you has thousands of copies of old and new retrovirus genomes integrated into your DNA

• About 8% of your DNA is made up of these ancient genomes

Viruses are helpful,,,!!!

• Anti-bacterial agents• Phage typing of bacteria• Sources of enzymes• Pesticides• Anti-cancer agents• Gene vectors for protein production

Small Pox Virus Foot and Mouth Disease Virus (FMDV)

Delayed emergence of potatocaused by Tobacco Rattle Virus

infection

Damaged potato(spraing) caused by

Tobacco Rattle Virus infection

Mushroom virus X Escherichia coli cell withPhage T4 attached

Viruses are a significant part of the ecosystem, infecting every living thing

Capsid

Viral core

Envelope

General Properties of Viruses

• Viruses are extremely small• Viruses lack metabolic machinery• Viruses cannot survive on their own• Viruses cannot be grown on artificial media• Need always living cell for infection• “Organisms at the edge of life”

Viruses are parasite Viruses hijack host machinery and utilize it for

Building blocks such as amino acids and nucleosidesProtein synthesizing machinery (ribosomes)Energy in the form of adenosine triphosphate

A virus modifies the intracellular environment of its host in order to enhance the efficiency of the replication process.

Modifications might include production of new membranous structures, reduced expression of cell genes or enhancement of a cell process.

Viruses are living or non-living??Non living?? How? lead a kind of borrowed life

acellular

Living??Viruses belong to biology because they possessgenes,replicate, evolve, and are adapted to particular hosts,biotic habitats, and ecological niches

Viruses : They are the smallest and simplest form of

life on earth, which can replicate only in living susceptible cells

Virology: the science which deals with study of viruses

as causative agents of very important diseases that occurs in human, animals, plants and other living organisms (insects, bacteria,…)

In The Cow-Pock—or—the Wonderful Effects of the New Inoculation! (1802), James Gillray caricatured recipients of the vaccine developing cow

like appendages.

Bacteriophage/ Dengue Labwaqasch536@hotmail.com

THANK YOU!