Discuss lambda phage as an experimental system. How has it been used in biotechnology? Explain how it is used as a vector for the cloning of recombinant DNA. Why is it important to know about restriction enzyme sites in phage lambda DNA? How would a scientist use a restriction site map for lambda?© BrainMass Inc. brainmass.com October 17, 2018, 12:23 pm ad1c9bdddf
Lambda phage is a bacteriophage that is a viruses that infect the bacteria. It has genetic form of either DNA or RNA encapsulated by protein coat. The bacteriophage have a capsid that enclosed DNA or RNA and a tail fibers that attached to receptors on bacterial cell surface. Lambda phage infect bacteria and propagate in two possible scenarios: lytic life cycle and lysogeni life cycle. When the phages multiply , they kill their host and the life cycle is the lytic cycle. The other life cycle is the lysogeny cycle in which the phage grow and integrate their genome into the host chromosome replicating with the host for many generation. Bacteriophages are used as antibacterials agents. Phage display systems, and vehicles for vaccines delivery. They are also used for diagnostic purposes.
Phage therapy is using the lambda phage as antibacterial agent against viruses was started in 1896 and still is used today. Using phage therapy has it advantages and disadvantages compared to antiobiotics. The main advantage of phages is their specificity for the target bacteria that reduces the damage to normal flora of the host. The bacteria to be target must be known because baceriophages are self limiting in that they require their hosts to be constantly growing. If the bacteria pathogens the phage target are absent, the phage will not propagate for long period. They can replicate at the site of infection. If the bacteria become resistant to the phages, then the phages can naturally change and evolve to reinfect the resistant bacteria and making the bacteria sensitive to them. This is another advantage of phages over antibiotics.
The disadvantage of using phage therapy is that once the are injected into the body, they quickly disperse throughout the body and triggering the immune system to produce antibody ...
The solution discusses the lambda phage as an experimental system and how it as used in biotechnology.
lambda phage genome insertion
Integration of the lambda phage genome into the E. Coli chromosome involves:
A Staggered cleavage of viral DNA, formation of a blunt-ended double strand break in the bacterial DNA, joining of the ends of the two DNA molecules, gap filling by DNA polymerase, and ligation of the last phosphodiester bond.
B Staggered cleavage of the viral and the bacterial DNAs, exchange of ends to generate a short heteroduplex region, and resealing.
C Double strand cleavage of the cellular DNA target site, followed by double-strand break repair, using the viral DNA as the donor.
D blunt-ended double-strand breakage in both DNAs, followed by rejoining with no heteroduplex formation.
E Double-strand cleavage of cellular DNA, annealing of a 3'-end in cellular DNA to a site in the viral DNA, replication across the viral genome, followed by another strand cleavage, and ligation of the last phosphodiester bond.