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.
Q. Explain about Metabolic diseases? Metabolic diseases, as you already know, refer to those disorders in which the various reactions in the cells are effected (production of e
Placenta - Human Development We had said previous in the unit that in the second week of development a primitive uteroplacental circulation is established. Early in this stage
Tissue Valves : Tissue valves mounted on a frame with a sewing ring are inserted by the same technique as used in the case of prosthetic valves.
An island may be colonised by just a few individuals, or just a pair:, or even a single gravid female. When a new population develops from these early colonisers of the island, the
Define Tips that should be followed before an event Start? Before the event, following tips should be followed: As the glycogen stores may be used up during night, a h
Classification of Living Organisms The world of living organisms is extremely diverse. Biologists call these diverse forms 'species'. It is estimated that over fifteen lakh (1
Mechanisms for Response – Protozoan Protozoa are sensitive to many kinds of stimuli like touch, temperature changes, light, chemicals, etc. It is not clear how they do so but
Lamellar compaction and remodeling (6 to 18 weeks) A remodeling phase is initiated in which hematopoietic-derived osteoclastic cells form cutting cones will remove the establis
Q. Are gametes always made by meiosis? In the haplontic haplobiontic life cycle and in the plant life cycle (diplobiontic life cycle) gametes are made by mitosis and not by mei
Explain the drawback of protein hydrolysates The drawback of many protein hydrolysates, is that when hydrolysed, most of the food proteins liberate bitter tasting peptides, wh
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