vector 3 (bacteriophage) in Recombinant Technology

vector 3 (bacteriophage) in Recombinant Technology

1. BSc Biotechnology 3 nd year V Semester BBT 502- Recombinant DNA technology Ganesh Nawkar Lecture3: Bacteriophages (NIH, Glossary)

2. General introduction to bacteriophages viruses that specifically infect bacteria Simple in structure with DNA (sometimes RNA) as a genetic material DNA codes for genes important for replication and proteins necessary for the protective cover of genetic material known as capsid

3. The general pattern of infection by bacteriophages Lytic cycle: Rapid infection by bacteriophage DNA replication is immediately followed by synthesis of capsid proteins the phage DNA molecule is never maintained in a stable condition the new phage particles is associated with lysis of the bacterial cell

4. The lysogenic infection cycle of bacteriophage λ lysogenic infection is characterized by retention of the phage DNA molecule in the host bacterium Prophage : The integrated form of the phage DNA Lysogen : a bacterium that carries a prophage

5. The infection cycle of bacteriophage M13

6. The differences between λ and M13 infection cycle integrated into the bacterial genome and become quiescent Follows lysogenic infection cycle first then lytic phase to release new phage particles Does not integrated into the bacterial genome and active Follows only infection lysogenic λ bacteriophage M13 bacteriophage

7. Gene organization in the λ DNA molecule Lambda = head-and-tail phase Polyhedral head contains DNA and tail serve as attachment to host bacteria λ DNA molecule= 48.5 kb λ genetic map is that genes related in terms of function are clustered together in the genome Clustering is important

8. The linear and circular forms of λ DNA