What roles do restriction enzymes, vectors, and host cells play in recombinant DNA studies? What role does DNA ligase perform in a DNA cloning experiment? How does the action of DNA ligase differ from the function of restriction enzymes?

The human genome is 3×10⁹bp in length.How many fragments would be predicted to result from the complete digestion of the human genome with the following enzymes: Sau3A (˘GATC), BamHI (G˘GATCC), EcoRI (G˘AATTC), and NotI (GC˘GGCCGC)?

The human genome is 3×10⁹bp in length.How would your initial answer change if you knew that the average GC content of the human genome was 40%?

Ligase catalyzes a reaction between the 5′ phosphate and the 3′ hydroxyl groups at the ends of DNA molecules. The enzyme calf intestinal phosphatase catalyzes the removal of the 5′5′ phosphate from DNA molecules. What would be the consequence of treating a cloning vector, before ligation, with calf intestinal phosphatase?

One of the major causes of sickness, death, and economic loss in the cattle industry is Mannheimia haemolytica, which causes bovine pasteurellosis, or shipping fever. Noninvasive delivery of a vaccine using transgenic plants expressing immunogens would reduce labor costs and trauma to livestock. An early step toward developing an edible vaccine is to determine whether an injected version of an antigen (usually a derivative of the pathogen) is capable of stimulating the development of antibodies in a test organism. The following table assesses the ability of a transgenic portion of a toxin (Lkt) of M. haemolytica to stimulate development of specific antibodies in rabbits.Immunogen Injected Antibody Production in SerumLkt50*—saline extract +Lkt50*—column extract +Mock injection -*Lkt50 is a smaller derivative of Lkt that lacks all hydrophobic regions. indicates at least 50 percent neutralization of toxicity of Lkt; indicates no neutralization activity.Source: Modified from Lee et al. (2001). Infect. and Immunity 69:5786–5793.With regards to development of a usable edible vaccine, what work remains to be done?

One of the major causes of sickness, death, and economic loss in the cattle industry is Mannheimia haemolytica, which causes bovine pasteurellosis, or shipping fever. Noninvasive delivery of a vaccine using transgenic plants expressing immunogens would reduce labor costs and trauma to livestock. An early step toward developing an edible vaccine is to determine whether an injected version of an antigen (usually a derivative of the pathogen) is capable of stimulating the development of antibodies in a test organism. The following table assesses the ability of a transgenic portion of a toxin (Lkt) of M. haemolytica to stimulate development of specific antibodies in rabbits.Immunogen Injected Antibody Production in SerumLkt50*—saline extract +Lkt50*—column extract +Mock injection -*Lkt50 is a smaller derivative of Lkt that lacks all hydrophobic regions. indicates at least 50 percent neutralization of toxicity of Lkt; indicates no neutralization activity.Source: Modified from Lee et al. (2001). Infect. and Immunity 69:5786–5793.What general conclusion can you draw from the data?