Question

In a class room seminar on cloning vectors, your friend asked to explain the steps to introduce the plasmid DNA to a bacteria cell, Micro injection and biolistics. Answer his questions.

Answer 1

For this, bacterial cells must first be made ‘competent’ to take up DNA. This is done by treating them with a specific concentration of a divalent cation, such as calcium, Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 42⁰C (heat shock), and then putting them back on ice. This helps to introduce the plasmid DNA into bacterial cell.

Micro injection – In this recombinant DNA is directly injected into the nucleus of an animal cell. 

Biolistics – In this cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA.