T7 BACTERIOPHAGE.pptx

Type of bacteriophage

1. T7 BACTERIOPHAGE M.AFREEN AZEELA III-B.SC MICROBIOLOGY

2. INTRODUCTION Bacteriophages are viruses that infects and replicate only in a bacterial cells. The word bacteriophage literally means BACTERIA EATER.

3. T7 BACTERIOPHAGE T7 Bacteriophage is a virus that infects susceptible bacterial cells that is composed of DNA and infects most strains of Escherichia coli . T7 has a lytic life cycle

4. In a 1945 study by DEMEREC and FANO,T7 was used to describe one of the seven phage type members that grow lytically on Escherichia coli. DISCOVERY

5. HOSTS T7 grows on rough strains of Escherichia coli and some other Enteric bacteria. It also infects smooth and even capsulated strains. It infects E.coli0157;H7 , a strain of E.coli that can cause foodborne illness.

6. STRUCTURE Complex structural symmetry. Capsid is icosahedral in shape. Capsid – 55nm in inner diameter. Head – 60nm in diameter. Tail – 19nm in diameter. Long attachment – 28.5nm in diameter. Non-Enveloped. Tail is non-contractile. Tail has 6 short sub terminal fibres.

7. GENOME The genome of phage T7 was among the first completely sequenced genomes and was published in 1983. The head of the phage particle contains the roughly 40kbp linear dsDNA genome which encodes 55 proteins.

8. LIFE CYCLE

9. TIME DURATION T7 has a short life cycle of 17min at 37’C . The time for the infection to the lysis of the host cell when new phages are released.

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