Transduction

Is a type of horizontal genetic transfer Donor DNA is picked up by a bacteriophage and released into the recipient cell The recipient cell becomes a recombinant cell The recombinant cell usually acquires new characteristics such as antibiotic resistance

Transduction Bacteriophage – Virus – infects bacteria Transducing particle Amp Res. gene

T4 phage that was used here to infect the E T4 phage that was used here to infect the E.coli strains was grown in Ecoli that is resistant to amp resistance Some of the transducing particles have amp res gene – lysate has phage and transducing particle T4 phage has a mutation where a codon for an amino acid has been changed to a stop codon UAG which is known as amber codon. Mutation that changes a sense codon to amber codon is known as amber mutation

Amber mutation prevents the synthesis of capsid protein of the phage such that phage cannot reproduce in a normal cell. Stop codon stops synthesis of protein because no tRNA with complementary anticodon. However transducing particle can inject the donor DNA into the recipient cell. In the BE strain phage cannot reproduce, but transducing particle can make transductants (recombinant cells) that are amp res.

The cells that are growing on the amp medium are transductants (recombinant cells). Normal cells are killed by amp not the phage. Resistant to amp, received amp res. Gene from a transducing particle. No phage plate – should be no growth . control to verify that without the addition on phage, No amp res cells.

More colonies non dilute (10X) than 1 to 10 10X more colonies in 1:10 than 1:100

CR63 has amber suppressor mutation Mutation in tRNA such that it has a anticodon complementary to the UAG (amber codon) which brings serine to the ribosome. Capsid proteins are made. Phage reproduces and lysis of cells. No phage – growth , see what a normal plate of CR63 looks like

Phage plate – less growth or no growth compared to no phage. Most of the cells are being destroyed by phage. Phage is killing the cells.