Bacterial Conjugation

As we learned in class, gene transfer in bacteria can occur through transformation, transduction, and conjugation. In this post, I will be focusing on conjugation. In conjugation, there is direct contact between the donor cell and the recipient cell through which a strand of DNA is transferred. See the picture below for a visual of how conjugation occurs. It has been found that conjugative plasmids contain genes that are resistant to several types of antibiotics. Therefore, if resistance to a particular antibiotic is selected, resistance to other types of antibiotics will be simultaneously selected. Plasmids involved in gene transfer also code for conjugative pilli that facilitates the transfer of DNA by binding to the recipient cell from the donor cell. At the end of conjugation, both cells have the plasmid that was transferred.



According to my article, this is the main method of the transfer of antibiotic resistance between bacteria. It may be useful to develop a method of preventing conjugation in order to prevent the development of bacteria that are resistant to multiple antibiotics. Several decades ago, it was found that filamentous bacteriophages are capable of preventing conjugation. Further investigation showed that this was accomplished by closing up the conjugation pilus (or sex pilus). This is mainly mediated by g3p, a phage protein within the phage coat that seems to lower conjugation rates. These results indicate that certain proteins from the phage can be used to slow down antibiotic resistance in bacterial cells.

Click here to view the abstract of the article I used and click here to view the full article.