Genetics4 - Genetics of Viruses and Prokaryotes ( c h a p...

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Co In E Genetics of Viruses and Prokaryotes (chapter 13) • Virus life cycles (pg 283-289) – Bacteriophages – Influenza virus compare to HIV • Regulation of Gene Expression in Prokaryotes (pg 296-300) – Lac operon – Trp operon • Plasmids and Prokaryotic genomes. ! " Co In E What are viruses? = sub-microscopic infectious agent that is unable to grow or reproduce outside a host cell. Viruses are not alive • no metabolic activity outside a host cell. • don’t take in nutrients or produce waste. • don’t grow. • requires host cell machinery to reproduce Viruses are tiny. Eg the HIV is 100 times smaller than a typical human cell In spite of all this, they have a great impact on our lives, causing many diseases Co In E May 1997 a 3 year old boy in Hong Kong developed a cough and fever Fever progressed to lung failure - boy dies Cultured fluid from his lungs - found influenza virus particles Mutation of a bird virus results in human infection Nucleotide sequence of the virus in the chicks and boy matched Little boy had been infected with H5N1 = flu virus only known to infect chickens, but a mutation in gene for virus surface glycoprotein made the avian virus capable of binding to and infecting humans December - 18 people were infected and 6 died of bird flu Tests of live chickens from markets revealed high rate of H5N1 infection Health officials ordered slaughter of all chickens (1.5 million chickens) Major epidemic avoided Co In E Influenza A virus strains Are categorized according to two surface proteins hemagglutinin (H) and neuraminidase (N) All influenza A viruses contain hemagglutinin and neuraminidase, but the structures of these proteins differ = rapid genetic mutation Influenza A virus strains are assigned an H and N number There are 16 H and 9 N subtypes known in birds, but only H 1, 2 and 3, and N 1 and 2 are commonly found in humans. Hong Kong bird flu = H5N1
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Co In E Viruses and Human Health The "Spanish Flu" pandemic of 1918-1919 was one of the deadliest plagues in human history, killing as many as 50 million people. Avian H5N1 Influenza virus – similar to 1918 virus
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This note was uploaded on 10/08/2010 for the course MCDB MCDB 1A taught by Professor Senghuilow during the Summer '09 term at UCSB.

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Genetics4 - Genetics of Viruses and Prokaryotes ( c h a p...

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