The exchange of Genetic Material between bacteria or How bacteria acquire resistance to antimicrobial agents in nature

Modes of genetic exchange transformation phage mediated transduction conjugation transposition

Transformation of bacteria with linear DNA— some cells are naturally competent for the uptake of DNA

Plasmids are autonomously replicating circular DNA molecules that can be used to artificially transform bacteria— naturally competent cells can take up a plasmid, such plasmid does not need to integrate with the chromosome for maintenance!!

Generalized transduction mediated by bacteriophages

Conjugation —a mechanism by which mobilizable plasmids can be transferred from one bacterium to another Note tra genes, oriT and antibiotic resisitance genes

Note conjugation bridge formed between donor and recipient cells Conjugation—a mechanism by which mobilizable plasmids can be transferred from one bacterium to another

Mobilizable plasmids can integrate into the bacterial chromosome —therefore bacterial genes can be transferred.

Transposons that carry antibiotic resistance genes can randomly “hop” into a bacterial chromosome

Mechanism for transposition AB R