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Genetics overview

Lateral or horizontal gene transfer

Incorporation of new DNA = “Recombinant”

Fig. 8.25

Transformation

Can be DNA fragments or plasmids.

Fig. 8.24

Transformation

Plasmid transfer via conjugation

Pilus

Bacteriophage - bacterial virus

Transduction

Non-functional virus

E. coli O157:H7 has a shigalike toxin acquired through transduction.

Very unlikely to happen, but when it does …

E. coli O157:H7 in Walkerton, Ontario water supply.

Infected 600 - 1,000 of 4,800 residents, 7 - 9 deaths.

Chapter 13-Viruses

UNIT 3 - Microbial Genetics and Viruses

I. Microbial Genetics

II. Viruses

A. General characteristics

1. Distinctive features - nucleic acid, protein coat, obligately intracellular, specialized structures

2. Host ranges

3. Sizes

B. Structure

1. Virion

2. Nucleic acid

3. Capsid and envelope

4. Morphology - helical, polyhedral, complex

C. Multiplication

1. Bacteriophages - lytic and lysogenic

2. Animal viruses

D. Viruses and viral infections

E. Prions

Foot and mouth

Great Britain - 2001

Foot-and-mouth facts

Confirmed cases: 2,030

Cattle slaughtered: 595,000

Sheep slaughtered: 3,306,000

Pigs slaughtered: 142,000

Other animals slaughtered: 4,000

Total animals culled: 4,047,000

Countryside Agency puts cost to

UK farming at up to £2.4bn

http://www.guardian.co.uk/footandmouth/flash/0,7365,443772,00.html

West Nile Virus

West Nile virus (WNV) is a single-stranded RNA virus of the family Flaviviridae, genus Flavivirus. Flaviviruses share a common size (40-60 nm), symmetry (enveloped, icosahedral nucleocapsid, nucleic acid single stranded RNA approximately 10,000-11,000 bases), and appearance in the electron microscope.