Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Bacteriophage Vectors
Bacteriophages are viruses that attack bacteria. Mainly phage lyses the bacterial cells they infect (lytic phages). But many others may choose to follow either lysogenic or a lytic cycle; in the second situation, the phage chromosome integrates into the bacterial chromosome and multiplies with the latter as prophage (temperate or lysogenic phages). The prophage can dissociate from the bacterial chromosome and follow the lytic cycle. Many bacteriophage are used as cloning vectors, the most generally used E. coli phages being λ (lambda) and M13 phages. Plasmid vectors have to be introduced into bacterial cells which are then cloned and choose for the recovery of recombinant vectors. In contrast, the phage vectors are sprightly tested to an suitable bacterial lawn (a constant bacterial-free zone in the bacterial lawn). Phage vectors show two advantages over plasmid vectors. (1) it is easier to screen a large number of phage plaques than bacterial colonies for the identification of recombinant vectors.(2) They are more efficient than plasmids for cloning of large DNA fragments; the largest cloned insert size in a λ vector is just over 24 kb, while that for plasmid vectors it is less than 15 kb λ Phage Vectors The λ genome (total 48,502 bp) contains an source of replication; genes for head and tail enzymes and proteins for DNA replication lysogeny and lysis; and single-stranded protruding cohesive ends of 12 bases (5' GGGCGGCGACCT; the other end is opposite to it; i.e.CCCGCCGCTGGA 5'). The λ genome remains linear in the phage head, but within E. coli cells the two cohesive ends anneal to make a circular molecule essential for replication. The sealed cohesive ends are known cos sites that are the sites of cleavage during and are essential for packaging of the mature phage DNA into phage heads. The λ DNA need to be larger than 38 kb and smaller than 52 kbto be packaged into phage particles. The genes for lysogeny are situated in the segment among 20 and 38 kb; the complete or a part of this segment is deleted to create λ vectors to (1) accommodate larger DNA inserts and (2) to ensure that the recombinant phage is always lytic.
Kingdom Protista The protistans are a complex and diverse group of organisms that are placed together simply because they are all single celled eukaryotes but some form rather sp
Q. Give the biological effects of aflatoxin and List the various natural toxins present in food? Biological effects of aflatoxin include hepatotoxicosis, carcinogenesis and liv
GIRDLES - (i ) PECTORAL GIRDLE - 4 bones. It is located on posterolateral part of upper region of the throax. It consists of scapula & clavicle. Scapula is placed
Why is quarrantine a must before introduction of a plant species from a dissimilar country? a) What is meant by apoplast pathway? Why does it occur in cortex and not in endoder
Determine about the prokaryotic cell While we describe in detail the structure of a eukaryotic cell, it will be useful to examine the structural features of a typical prokaryot
types of excretory system of lower animals
What is the importance of mitosis for the embryonic development? Every embryo grows from a single cell that suffers mitosis and operates other cells that also divide themselves
Define Blank titration for Determination of the Iodine Number of Lipids? Using an autopipette, measure 25 ml of Hanus iodine reagent accurately and transfer into a 250 ml iodin
Explain Food plan for an anaemic pregnant lady? Justification of the Plan: The plan is for an anaemic pregnant lady, from a lower socio-economic level and doing moderate lev
Q. From which features do osteichthyes and condrichthyes get these names? "Chondros" means cartilage, "ictis" means fish (both from the Greek) the name chondrichtians is for fi
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd