Plasmid analysis Essay Example | Topics and Well Written Essays - 1500 words

Plasmid analysis - Essay ExampleThe blue plasmid desoxyribonucleic acid did not contain any of the travail sites for Hind III or Sac I. Introduction Plasmids are the extra chromosomal desoxyribonucleic acid molecules which are mostly double stranded, circular and covalently closed molecules, varying in size from 1 kb to 200 kb. (Sambrook and Russell 2001). They are found in many bacterial species. They repeat independently and use a pastiche of mechanisms to maintain their copy number. They contain the gene codes for the enzymes that are important for the bacterial hosts. The plasmids act as vectors in the molecular biology experiments. The vectors are the carrier DNA molecules into which the foreign gene of interest is inserted and expressed in the host. This DNA is now called recombinant DNA (Roberts and Murray 1976). This recombinant DNA is able to express the Foreign DNA in the bacteria. These vectors replicate inside the host cell along with the inserted DNA. These vectors a re of two types expression vectors (expression of the cloned gene to give the desired protein) and cloning vectors (produce millions of copies of cloned DNA) (Sambrook and Russell 2001). Restriction endonucleases are the enzymes that cut the DNA at the specific sequences. There are about 200 different restriction enzymes (Siwach and Singh 2007). ... The restriction mapping is used to identify the plasmids. The number of DNA fragments and the size of the DNA fragments depend upon the action of the restriction enzyme (Kruezer and Massey 2008). These DNA fragments thus obtained are separated using the Agarose gel electrophoresis. Restriction mapping consists of three important steps. They are restriction enzyme digestion, agarose gel preparation and sample loading (Kruezer and Massey 2008). Results and Discussion The nutrient agar plate was inoculated with E.coli, and the antibiotic discs were placed in the four quadrants. Figure1 Antibiotic visibleness against tetracycline in E. coli DH5alphaE pMTL84445 After inoculation at 37 degree Celsius for overnight, it was observed that the antibiotic disc of tetracycline had a clear zone. This indicates that the E.coli culture is repellent to kanamycin, chloramphenicol and ampicillin. There is very little sensitive to tetracycline. Figure 2 Antibiotic exemption profiling Table 1a Antibiotic resistance profiling of kanamycin control Kanamycin control E. coli DS941pRRK Antibiotic disc Zone diameter in mm Chloramphenicol 30 Kanamycin 0 Tetracyline 10 ampicillin 0 E.coli DS941pRRK bacteria was found to be very sensitive to Chlormaphenicol and comparatively sensitive for Tetracycline antibiotics. The bacteria showed resistance to kanamycin and Ampicillin. Table 1b Antibiotic resistance profiling of chloramphenicol control Chloramphenicol control E. coli DS941pAV35 Antibiotic disc Zone diameter in mm Chloramphenicol 0 Kanamycin 27 Tetracyline 32 Ampicillin 0 E. coli DS941pAV35 bacteria were found to be very sensitive to K anamycin and Tetracycline and resistant to Chloramphenicol and Ampicillin.